Photography / Tips and Solutions

How to Test Your Lens

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So, you just bought a shiny, new, and maybe expensive, lens for your camera, and being the savvy consumer, you did your homework. You pored over customer reviews on the B&H Photo website, read online reviews splattered all over the Internet, grabbed a copy of every photo magazine that reviewed the lens, bookmarked dozens of websites, and now have the lens’s MTF curve charts burned into your retinas.

Now, your lens is here and it is time to go out shooting. Honestly, not a problem. Your lens should be as good as it can be and, as photographers, we want to take photos. So, stop reading and go out and make some photographs!

Still here? OK, let me tell you why you might want to test that lens yourself. The main reason is that even with today's precision computer-controlled manufacturing techniques, there are variations in each and every lens that rolls off an assembly line. This means that some examples will be better than others. Some lenses will be outstanding and others will make you wonder if all of those glowing reviews you read online were completely bogus.

I once purchased a new 40mm lens that was advertised and reviewed to be, based on all reviews, incredibly sharp. The Internet is full of tests that show this is a superb lens. I spent some good money on this lens and hurried home to try it out. However, me being me, I took the new lens out for a shoot with my tried-and-true 50mm f/1.8 lens in the bag. I took the same photos with the two lenses, albeit at the slightly different focal lengths, and hurried home. After analyzing the images, I was left to speculate that, either the reviews are full of lies about this 40mm lens, that I got a bad example of this lens, that my 50mm f/1.8 is the most awesome lens ever made, or a combination of those possibilities.

"I like to test my lenses to determine where in their aperture range and focal range (if a zoom) they are performing at their best."

Had I not had a lens to which I could compare it, I might have been happy with the performance of the 40mm and not known the difference. But, because I did a quick test of my new lens, comparing it to a lens that I was familiar with, I was able to determine that it should be returned to the store and my money saved for something else.

Knowing that no two lenses are the same, as far as performance, why else would we want to test a lens? For most of my photography, I want to maximize the sharpness of an image. In order to do that, I like to test my lenses to determine where in their aperture range and focal range (if a zoom) they are performing at their best. A lens’s sharpness and degree of vignetting will change based on the aperture selected, as well as its focal length, if it is a zoom.

Before We Begin

The goal of this article is to give you some pointers on how you can do some basic lens testing at home. To do that, I will share with you techniques I have used to test my lenses. There are two parts to my lens-test goal:

  1. evaluating the lens’s performance,
  2. getting the testing out of the way so that I can go out and make photos.

There are a lot of people out there who go absolutely nuts with lens testing. So, if, after you read this, you find yourself building a dust-free clean room in your home, walking around in a lab coat, and trying to figure out ways to shoot laser beams through your lenses onto a computerized target sensor for dispersion analysis, you may want to consider a new career with some of the more well known lens-testing websites and magazines.

Also, as anyone with an Internet search engine can attest, there are many different opinions and techniques regarding how to test lenses. I generally test my lenses for sharpness. However, you can test for vignetting, symmetry, distortion, focus, and other factors in the comfort of your own home without fancy gear. So, feel free to share your ideas and methods at the end of this article, but please know that what I am sharing here is, simply, my personal technique and I am not suggesting it is the only way, or best way, to test a lens.

Mental Prep

Before we get into the gear needed, you should, if you have it, turn on the part of your brain that may have been lying dormant since grade school science classes. The testing of your lens is an experiment and you need to have a basic scientific mindset to make sure you do not have to go back and repeat the tests over and over again. What do I mean? You need a plan in place before you get started. Have paper and a pencil handy to take notes. Photography can be done “from the hip,” but good lens testing needs a methodical approach. Don’t worry, we aren’t doing crazy stuff here, just know that a bit of pre-organization and a good plan will make it all go smoother.

Also note that there will not be a “control” for this experiment. If we all owned an optically perfect lens with which to test all others against, we would not have to test our lenses, right? So, your lenses, with their inherent flaws, will either be tested against themselves or other flawed lenses.

Gear Prep

The most crucial piece of gear you will need for a lens test is a tripod. If you do not have a tripod, you will not be able to perform an accurate lens test. Period. No one that I know can handhold a camera completely steadily. Going back to the scientific process mentioned above, we need to eliminate as many variables as possible when performing our tests. Movement is something we need to eliminate in both our camera and target. I highly recommend using a remote shutter release (cable, electronic, or wireless), and if using an SLR camera, the mirror lock-up mode to reduce vibrations. 

The Targets

I have been told that a famous photographer once said, "I do not photograph test targets.” Well, I do. But, I am not famous. Yet.

There are lots of things you can photograph to get a solid lens test. You can do it indoors or outdoors. You can create your own target, buy a target, or print one from the Internet. You can use what is around you. The possibilities are endless, as are the opinions about what works best.

Full-resolution image available by clicking on the illustration above.

Test targets are versatile and can be used for a variety of tests. Some, like the ISO 12233 chart and USAF 1951 Resolution Test Chart, will come up on most web searches. Personally, I located the highest-resolution chart I could download and then I had it printed on photo paper at a big box store at 20 x 30" and dry-mounted on foam core. I was tempted to mat and frame it for permanent display, but all of the wall space in my home was already taken up by photos.

Is a printed test target a perfect target? No. If you want to get crazy, you can spend a lot of money on laser-etched glass targets that are used for calibrating things that are way more precise than your camera and lenses. A printed test target will be your least expensive option.

Some folks will make a homemade diorama with different objects (wine bottles, color charts, tourist trinkets) to photograph in one scene. This is fun and works well for the test, but the problem is, unless you have very understanding roommates or the only key to your photo cave, you will have to put all the objects away when you are finished and you might not be able to recreate it perfectly in the future. The two-dimensional test target gets put away into the closet when I am finished.

Do you need a dedicated target to perform a lens test? No. You can simply go outside and point your camera at something in “real life.”

I kind of cringe when I go to a camera/lens review test website and see photographs of trees as a test target. Why? Well, trees move when the wind blows. Remember what I said about eliminating variables? When I do a lens test outside, I look toward manmade structures (usually stuff that humans make has a ton of right angles and sharp edges) and I try to put lettering of some sort (street sign, license plates, storefront signage) in the center and corners of the image. Remember, you are testing your lens, not creating the greatest photograph on the planet, so don't worry about composition and all the other things that you might usually consider before taking a photo.

Also, you want the things you are going to study in the image to be as close to equidistant from you as possible. When shooting a target on a wall, level your camera and aim for a vertical wall. When outside, try to find a wall or scene in the distance that will have the center and edges of your frame about the same distance away.

I have found that a well-populated bookshelf is a great tool for lens testing. Remember what book you are targeting in the center of the frame and use the writing on the spines of the surrounding books to check your sharpness. Also, the shelves, if straight, can let you evaluate lens distortion.

Speaking of distortion, the “brick wall” is often mentioned in lens-testing circles. Not the worst idea, but I would hope to find one with some signage on it to give me some sharp edges and lines to look at in the images.

If you can do it, I recommend the test target for normal (around 50mm) and telephoto lenses (greater than 50mm) and a wall or bookshelf for wide-angle lenses.

The Plan

Many of us have a camera bag full of zoom lenses and prime lenses. If you have only one prime (fixed focal length lens) to test for sharpness, your mission is simple. If you have a quiver full of lenses and many of them are zooms, you will thank me later for that suggestion to get paper and pencil ready.

For a normal or telephoto prime lens, I simply set up the tripod and camera at the distance where the target fills the frame, and then I take photographs as I run through the aperture settings. When out doing non-lens-test photography, I adjust my aperture in full stops to simplify the exposure math for me. I do the same for lens testing. If you adjust your aperture in half stops or third stops, you will get two or three times the number of test images to sift through and that might be enough to make this process less fun.

For zoom lenses, I roll through each aperture setting (full stops again) at the focal lengths marked on the barrel, which usually correspond to popular prime lens focal lengths (85mm, 105mm, 135mm, etc). Of course, I will always test the zoom at the widest angle and the greatest, as well, even if they do not correspond to popular fixed focal lengths.

This is where a little planning helps. Say you are evaluating an 85mm f/1.8 prime lens, an 85mm f/1.4 prime lens, and a 70-200mm f/2.8 zoom lens. You can mount each 85mm lens and roll through the apertures, but, before you move your tripod you might want to grab the 70-200mm lens, set it to 85mm, and test at that focal length. Take notes. The image metadata will help remind you what you were doing later, but it is good to have a check-off sheet tracking your progress, so you do not waste time by repeating tests.

Also, if you are testing older, manual focus, pre-electronics lenses, your notes will help you when and if the metadata does not recognize the lens or aperture setting. When I test my manual focus lenses, I try to set up the test so that the targets fill the frame, while allowing me to focus the lens at infinity in an attempt to eliminate focus errors.

Afterward

Well, you just took several dozen pictures of a test target, bookshelf, wall, or city scene. Now you get to spend some time in front of the computer analyzing the data. I start by re-naming the files with the focal length of the actual shot, and the aperture plus the name of the lens. Example: 105mm f8 - Nikkor 70-200 f2.8 AF.jpg. Then, when finished, I can easily compare the shots from a certain lens or a certain focal length by opening just those images on my screen.

Still got your paper and pencil handy? Open a series of images (single lens or single focal length) and start comparing the visual sharpness of the center of the images and the corners. Take some notes. You can also evaluate the images for vignetting and symmetry, as well. For symmetry, verify that the lack of sharpness in the corners is the same for each side of the lens. For vignetting, you can push the contrast and levels sliders to see if the corners darken.

When I compile my notes, I type them up and send the file to myself in an email, saving the notes on my smartphone. Now, when I am out shooting, I can quickly remind myself that my 50mm f/1.8 is slightly sharper in the corners at f/5.6 than at f/8 and that when I go below f/2.8 I start to lose sharpness noticeably.

Mission accomplished. Let us know if you have different proven techniques or questions. Thanks for reading and good luck with your do-it-yourself lens tests!

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Thanks for the great article Todd. I have an old Nikkor 50mm 1.8 AI S 400,000 series lens I use on my D200 camera.This 6 element lens seams to be sharper in the mid aperature ranges than my 7 element 50mm 1.4 lens that I bought with my Nikon F back in 1969. I'm  going to use your lens testing technique to check check out both lens. Do you know anything about this 50mm 1.8  pancake style lens?

Thanks,

Ev Greer

 

Hey Ev!

That older 50mm f/1.8 AI S lens is one of my favorites! I have one on my Nikon FM3a all the time and have used it on my digital cameras as well. I owned most of the Nikon 50mm lenses before the G-series lenses arrived and I always found the 50mm f/1.8 lenses to be superior to the 50mm f/1.4 versions. Nikon didn't change the optics of the 50mm f/1.8 for several generations of lens barrels—a good thing!

I am sure the new G versions are great, but that older pancake lens is really fun to use and a perfect size!

The old 50mm f/2 is just as sharp in the mid apertures and you can find them at thrift stores for less than $20 these days!

Thanks for writing in!

My 1960s vintage 50 f/2 is the sharpest lens I have used owned, including hassy 6cm x 6cm and  Schnieder 4x5 glass.

It was a great lens! I sold mine only because I didn't like the 6-pointed sun stars it produced. 

https://www.bhphotovideo.com/explora/photography/tips-and-solutions/create-compelling-star-effects-sun-stars-starbursts-photos

Thanks for writing in, Paul!

I am looking for the Program to evaluate images, in Afterwards I can't find this info.

So how do you evaluate /view images?

Thank you Daniel

Hi Daniel,

There are a lot of different software options for viewing test images, including the default software that comes with most systems.

I personally use Lightroom or Photoshop, but those are powerful programs that aren't required for simply opening test shots and zooming into them to check image sharpness.

Thanks for reading!

50mm is probably the only lens you 'll need . This probably applies if you have a camera full-frame , but still, if you have an APS-C, this lens will be an excellent investment. Both Canon and Nikon, the 50mm f / 1.8 lens is the cheapest they have for sale. Depending on the country, the price ranges between 100 and 120 dollars, so it is an excellent choice if you manage a budget. This lens will allow you to achieve images that kit lens can not perform. Having an opening of 1.8 lets you work with a depth of field very small and can explore portrait photography otherwise .

Definitely an excellent choice. If you have anything more capital, you can invest in a 50mm f / 1.4 or better yet, a 35mm f / 2 if your camera's APS-C. They are somewhat more expensive, but worth every penny by yabeshphotography

I am a big fan of the 50mm f/1.8. Thanks for posting, yabesh!

I like the signs on wall I like same image at varying light and f/stops.. I test bokah too. 

If I shoot again and again the same wall etc it's best as I can compare to lens shot 6 months ago 

Thanks for reading and sharing your tips, Matthew!

Flat is not equidistant! Basic math there!!!! Ha

Yep, that is why I said, "as close to equidistant as possible."

But, truth be told, I am not good at basic math.

Hi, I really like this article thank you.  So I am an amateur aerial photographer, and I have just replaced the standard lense on my drone to take advantage of a new lense that is suppose to be better with the new Sony sensor that came with this drone. After reviewing the data, it's almost like there is no difference.  I have not applied your testing concept yet, and most of the shooting that I do, I do with the default setting on the camera which are quite good.  Will the focus chart make a difference on these small lenses as well.  Thanks, Peter

Hi Peter,

Thanks for the kind words! I am glad you enjoyed the article.

My guess is that the chart will work just fine for your drone camera. Let us know if it works out for you! Good luck!

I'm brokenhearted. I just received my new Canon 24-70 2.8 L-II lens based on rave reviews about its sharpness across the entire range. Wow, it IS sharp, the sharpest lens I've looked through. The dilemma is the awful vignetting at 50mm. The first-generation lens is MUCH softer but doesn't have anything CLOSE to the vignetting of its replacement. The lens is going back. Dang.

Hey John,

There is nothing worse than a broken heart! Sorry to hear about your vignetting issues.

Do you have a UV filter on the lens? Is the filter ring slim? Have you read about others with that lens having the same problem?

I hope you just got a bad example and, if you get another one, that it works great for you!

Good luck!

Keeping the lens. Adobe Camera Raw dispenses with the vignetting. Magic happens right in front of me.
Service from B&H is stellar!

Thank you, John!

That would actually be my dream lens!  I LOVE vignetting and that lens would save me time in lightroom!  Hope your repacement lens works well for you.

The rulers are generally used to find if the lens is front or rear focusing; Lie the paper on a flat surface camera set to angle above, about 25 degrees is good. Set focus to center point focus. Then focus ensuring that your auto focus hits the center of the page (with this chart I would aim right at the ruler). Take the photo and review. Repeat for valid sample group. If the auto focus is correct the sharpest part of the image will be 10 (on this chart) on the ruler.

If you camera allows it you can then set micro focus adjustments until it's spot on. I have a Sigma 1.4, 50mm that was terrible until I did this - now my favourite lens!  

Hey Tim,

Thanks so much for the tips!

Luckily for me (knock on wood), I haven't experienced a focus issue with any of my lenses.

Thanks for reading!

Hi Todd,

Thanks for the article.  I have a question on sharpness:  can lenses lose it over time?  If so, is there anything that can be done to fix them?  I have a lens (Nikkor 18-105mm DX VR) that can't seem to take sharp photos anymore, even on a tripod with VR off.  I did a lot of home testing on it--different f ranges, shutter speeds, zooms, pre/post cleaning, tripod/handheld, two different bodies (D40 & D5500), live view vs. viewfinder, manual vs. auto focus--and can't figure out if there's something wrong with the lens or if it's just me.  I don't think it's a front/back focus issue (used Tim Jackson's focus test chart), but I'm not sure.

Thanks, Larry

Hey Larry,

This is kind of dangerous territory, so don't quote me here, but here is my guess...

Yes, lenses can become "less sharp" over time. This could be due to mechanicals wearing out, elements becoming misaligned slightly due to impacts, or perhaps due to fungus and haze in the optics. Are any of these the culprit for your lens? Only you can figure that out.

Also, if you upgraded your camera to one with higher megapixels, you might just be seeing that lens flaws are more noticeable with increased resolution—certainly something to think about if chasing the golden ring of megapixels! But, the fact that you are seeing it on two different bodies might cancel that argument. 

You could send the lens to Nikon for a diagnosis if you can live without it for a while.

I know this isn't an answer, more of a few hypotheses for you. I hope it was semi-helpful!

Thanks for reading and writing in!

To Jenny, re the Tamron 90mm, check that if it has VR, VR is off.  If it is on that will produce the effect you are seeing.

Thanks for helping Jenny, Steve!

Initially, she did have VR on, but still had issues after it was turned off. We are still troubleshooting.

Thanks for reading!

Hello,

Great article. I noticed the chart has some sort of "rulers" at top and bottom; can I find the lens resolution power by those? and how? It would be awesome too if the letters on left and right (with the small numbers) are explained. I think this chart has more to extract from other than simple CA and vignetting check.

Hey TJ,

We based our chart on one that we found on the web. The online chart did not explain the markings, so your guess is as good as mine!

Sorry I can't be more assistance. If you want to do some homework, feel free to find the other chart and see if you can contact the designer. I would be interested if you find any information out. Maybe I will go digging, too!

Thanks for reading!

Thanks!

In fact before commenting, I realized there are more complicated charts, like ISO 12233, which has lots of lines and the calculations are somewhere out there. That's why I preferred this one because of its simplicity. Anyway, it is good enough to check for chromatic aberrations and sweet spot testing. Later on, I want to check if I can define the correction parameters for some fisheye lenses in DxO, if that was possible. I've already written a blog post about testing my Canon EF 15mm fisheye lens and Voigtländer 20mm, and made a comparison between the two. I'm in the process of explaining the whole process step by step in my other Arabic blog. Thanks a lot :)

Hey TJ,

I emailed the creator of the ISO 12233 chart that I found on the web, but no reply yet. I'll let you know!

Let me know when you get the test results from your fisheye lenses!

Thanks!

I wrote a long blog post - which I hope it would be useful. I had some setbacks but well, I hope the results can be relied on.
You can check it out here: http://ayvarith.blogspot.com/2016/03/staidear.html

Thanks again! :)

Thanks, TJ! Looks like a comprehensive test. I hope the chart is working well for you.

Thanks for sharing!

Thanks to you for putting this up :)  and I hope my tests are up to the level :)

No worries! Good luck, TJ!

Thanks for a really helpful article.  I've bought two used lenses and always have wondered exactly how good they were.  Now, I'm considering another. 

I have 2 questions.  Have you done anything about how to physically examine a lens, what and how to check it for things like dust, scratches, fungus, haze, aperture movement, etc?  Or have a link to a good article or video?  Question 2 ... you said your favorite 50mm lens was a Nikon "non-D" version.  Can I ask what version it is?

Hi Jenny,

I am glad you enjoyed the article! Thanks for writing in!

I have two answers...

1) Checking a lens can be important. In general, dust will not have any effect on the image quality. If you hold an unmounted lens up to the light, you will likely see internal dust between lens elements. This dust cannot be removed outside of having the lens overhauled. Luckily, it really won't ever show up on an image. Haze and fungus can have a negative effect on the image quality, as can heavy smudges from fingers and such. For more on how to clean your lens, click here.

If you have a lens that allows you to manually select aperture, feel free to roll through that movement as well. If it is sticky or stuck, time for a repair. Also, look for oil on the aperture blades. This can be indicative of a mechanical problem. The blades are lubricated at the factory, but if they look unevenly covered, or worse, there is oil on the internal lenses, then it is time for a cleaning.

I don't know of a good video on this, but check out my article when you have a moment. Also, do a web search for "dirty lens article"...there is a great website where a fellow photographer shows you just how dirty your lens can be and still take great photos. You'll likely be shocked!

2) My favorite Nikon 50mm lens is the non-D version of the AF NIKKOR 50mm f/1.8D. It is optically the same as the D version, but I liked the different finish and feel of the lens. I have not had a chance to test the new G lenses, but, as I use the lens on other camera bodies (using adapters), it is important for me to have manual aperture control. In general, all of the Nikon 50mm lenses are excellent. One of the sharpest I have seen is the old manual focus 50mm f/2 lens. I parted with mine because I didn't like the sunstars it produced, but other than that it was scary sharp and I bought it at a thrift store for $15.

I hope these replies answered your questions! Let me know if you have follow-ups and thanks for reading!

Thanks for the reply, Todd.  It helped, and I did find some on-line info on physical examination of a lens also.

But, I'm still confused about your favorite lens.  Are there two different versions of the Nikkor 50mm f/1.8D?  How can  this 1.8D be a "non-D"?  Reason I'm asking is that I have a Nikkor 50mm f/1.4D lens, bought used.  It has a manual aperture control too.  Is it a "non-D" version?  I have a serial number, not a model number.

Also, I have heard that the Nikon 50mm 1.8 E Series is sharper wide open than any of the D or G series lenses.  Opinion?

Hi Jenny,

I am glad it helped!

Sorry for the confusion. There is only one Nikon 50mm f/1.8D lens. It is physically identical to the non-D version except that the non-D version had a slightly more matte finish and most of the D versions were manufactured in China and not Japan.

I have heard that conjecture about the E-version, but have never tried it. Supposedly, the optics are the same in the older manual focus version, the E, the AF non-D, and the AF-D version. When the E-series came out, people didn't like the fact that they were made of plastic. Now, that is the norm, but the E-lenses got a bad rap at the time because of it.

I have still yet to test the G...but likely won't because I need that manual aperture ring!

If you have a 50mm f/1.4D you have a great "D" lens. The G-lenses have no manual aperture; the D lenses do.

Have I confused you more? I hope not! Standing by for your next questions! Thanks!

Yes, I think I have a nice 1.4 D lens, but want to see if it's front or back focusing, also same for a new Tamron 90mm f/2.8 that I just bought from B&H.  I'm already seeing that both are sharper at certain distances and f-stops than others.  I'd like to find the sweet spot because I know they're both nice lenses.

I'm almost embarrassed to have another question, although this one may help other people looking at your article and comments here.  I downloaded your chart, set up to start taking shots, then thought about metering modes and how that could affect the outcome.  So that's my question.  Should camera be set on spot metering, tying to focus on the very center of the circle?  Or what?  If not spot focus, what mode and how many focal points should be used?  I set up to fill the frame with the chart.  I'm not a pro (obviously), but trying to understand all this ... I'm like a sponge right now, LOL!

Thanks for your quick responses ... it's often hard to get answers when you need them.

Hey Jenny-Sponge,

Thank you for all the questions. Seriously. I love getting mail, so keep them coming!

So, the idea with the test chart is that you want to fill the frame with the chart. However, if you think the lens is having focus issues, you should vary your distance from the chart and see if it is focusing accurately. Don't worry about corner sharpness and other things when you are checking for focus. There are a few websites that talk about how to test focus and make micro-adjustments (depending on the type of camera). I have never had the need to do this with my gear, so am definitely not an expert in that field (nor the lens test field for that matter...this article outlines the test that I use for my own stuff).

As far as metering, because you are likely testing your lens' sharpness at different apertures, you should set the lens to aperture priority and let the shutter speed change as needed to keep the exposure fairly consistent. Different shutter speeds will not effect sharpness. Different exposures (caused by different shutter speeds) will not effect sharpness as long as the camera is mounted on a tripod and you are using mirror lock-up and a release. Keep your ISO at the native. Noise will effect perceived sharpness in the final image.

And, yes. Use the central focus point and place it on the center of the target.

Looking forward to more questions and a holiday card!

Another challenge in response to your comments.  Why do people think they should "upgrade" to the 50mm G, when the D version is faster, has manual aperture, etc.?  Just because it's newer?

Good. I love challenges, Jenny-Sponge!

Well, there is a 50mm f/1.4G lens that is as fast (aperture-wise) as the 50mm f/1.4D, so dead heat there.

The advantages of the G lens are a new optical design, 9-blade aperture vs. 7 on the D, and faster and quieter auto focus. Nikon went away from the manual aperture rings claiming that the electronic aperture is more accurate and the lenses have a tighter fit on the camera body. Some have argued that that might be marketing hype to overshadow a manufacturing cost-savings measure.

The G lens is larger and heavier, a disadvantage for some.

Both are excellent lenses, but some upgrade just because they can and some upgrade because they thing one is superior to the other. For me, the manual aperture is important as I am shooting some of my Nikon lenses through an adapter on mirrorless cameras.

Thanks again, Jenny! Keep them coming!

I just tested my two primes with your chart and method ... think I got it right, but am a bit concerned about the results from my Tamron macro lens.  First, I was on a tripod, straight alligned with the target chart. Distance from camera to chart was set to fill the frame with the chart. Set to aperture priority, spot focus, ISO at 200, was on back focus, but used remote shutter release.  Same setup for both lenses.

Nikon 50mm f/1.5 D:  Very sharp from f/2.2 to f/8.0, consistent across the chart.  Not as sharp before or after this range, but not terrible anywhere.

Tamron 90mm f/2.8 Macro:  Sharp at f/3.5, f/4.5, f/6.3, f/9.0.  Some in-between were NOT as sharp.  Sharpness drops off bad after f/9.0, gets very blurry (unusable) as moving up to smallest apertures.  Also, I noted that there was more blur at on the right side of the chart than on the left.  Another concern was that as the camera auto-focused, the focus indicator in the viewfinder shifted downward, then came back up with shutter release.  I may have to test this again to describe it better, but my 50mm Nikon lens did not do this (and nothing was changed in camera settings).

So, what do you think?  Are my results fairly normal for the 50mm lens?  What do you think about results from the 90mm Tamron?  They seem strange to me.

Thanks for your help and input.

Typo error ... it's a Nikon 50mm f/1.4 D.

Hey Jenny,

Good morning!

Regarding the Nikon...those results are very similar to what I found with that lens. When you go wider than f/2.2 it starts to get soft, and, at the other end, diffraction sets in above f/11. It sounds like you have a good, normal copy of that lens.

The Tamron is a bit of a mystery. Diffraction above f/8 or f/9 is not uncommon for a lens, so that isn't too concerning to me. The asymmetrical sharpness is more of an issue, in my book. How long have you had the lens? Where did you get it from?

If you can return it, you may want to do that and see if you can exchange if for another copy. Or, buy a new one and see if the results are similar. If they are, its the lens' overall performance. If the new lens is better, then you have a defective copy and you should send it back to Tamron.

Yes, probably not what you wanted to hear. Let me know what you want to do and I can even mention this to our Tamron rep to see if he has any ideas.

Thanks again, Jenny!

I got the Tamron lens from B&H, in January.  Hadn't had time to even try it out until last week.  I'm going to test it further, without back-button focusing, see if that makes any difference.  I could e-mail you some pictures if that would help.

Hey Jenny,

Sure. Send me the photos to toddv (at) bhphoto.com.

Thanks!

-Todd

So it's been 12 months ago that you wrote this article and I don't see a PDF of the B and H chart mentioned in the article. Does that mean it's not going to happen?

Hi JP,

If you click on the B&H test target, the full-resolution file should open in a new tab or browser window. We just added a caption to point this out. Sorry about that!

Thanks for coming back to get the target! Good luck with your testing!

Also, if you can find others through a Google search. I made my own based on one that I found. Cheers!

thanks for a great article. My high school photography instructor would tape a page from the NY Times on the wall and use that to test his lenses. Very effective.  Thanks again.

Not a bad idea, John! Thanks for reading and sharing!

I like the idea of the newspaper test clip, simple and quick, and considering the very small print on newspapers it is a good test for sharpness and distortion.
About the amazing sharpness of the 50 mm lens this is to be expected since this is the focal length that is easiest to make high quality lenses. Also nearly all SLR cameras were sold with this standard lens, so it had to be high quality when a camera was tested in a photo magazine to make it sell.
No other focal length, whether wide angle, telephoto or zoom, can match the quality of a standard 50mm lens. It also has the advantage of being much cheaper in price than other lenses, has a big aperture of 1.8 or more, and small in size compared to other focal lengths.
So if you want the sharpest and best quality lens go for a 50mm lens, no matter the make.

Hey Jack,

I agree with you there, the 50 is a great lens to have. I have had a bunch and then narrowed my collection down to the Nikon 50 f/1.8 (non-D) lens as my favorite. A good 50mm is the smartest lens you can buy, in my opinion!

Thanks for reading!

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