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FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses 
Thread started 11 Sep 2010 (Saturday) 23:37
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How do you test your lens sharpness?

 
tkadrum
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Sep 12, 2010 13:54 as a reply to  @ post 10895094 |  #31

How do I test the sharpness of my lens?
Well, I would smash the lens, take the glass and cut my finger and see if it is sharp or not? (sarcasm on a Sunday..ugh)


Yes, you can call me Tom

  
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DavidR
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Sep 12, 2010 15:17 as a reply to  @ tkadrum's post |  #32

I have the same test for all lenses. My old hat, shot wide open.

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IMAGE IS A REDIRECT OR MISSING!
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And compare the images against my other lenses at a 100% crop

IMAGE NOT FOUND
IMAGE IS A REDIRECT OR MISSING!
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If it passes my test, its a keeper lens.

Sony a9II

  
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crn3371
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Sep 12, 2010 15:33 |  #33

I go out and use it. If the results look good to me, then it's sharp.




  
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wimg
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Sep 12, 2010 16:16 |  #34

six4 wrote in post #10895024 (external link)
lol. I almost feel as though my bringing up the shooting of charts to test lens sharpness is offending many people on this board

I just always read how people say their lenses are "super sharp" and have always wondered if people had a system in which they used to compare sharpness. I guess to my novice eyes - without a system in place - all my lenses look very sharp.

I apologize for asking a question that seems to peak some serious dissent

Shoot with your lenses so that the framed image is the same size, and compare those. Preferably of a subject with plenty of detail. A brick wall with reasonably varied bricks set in rough mortar (where you can easily see the grains of sand used to make the mortar) will do.

Thsi way you can compare all of your lenses the same way. Not that the same frame is very important here (and difficult to achieve), although you can measure out a distance of, let's say, 50X the FL, to achieve this.

Also note that focusing is critical in this case, and therefor also stability. SO use a good tripod, LiveView at 10X for critical (manual) focusing, mirro lock up, and a remote switch. Count at least ten seconds between touching the camera/flipping up the mirror, before actually taking the shot. Also, take several shots at the same aperture, focused slightly different each time, and use the sharpest of the shots for comparison.

As others said, sharpness is not the be all and end all though. Often the overall rendering and pleasing bokeh is much more important. The latter two are difficult to measure, however, as they are very personal to the shootist.

As to super sharp vs sharp: many people do show a super sharp image, or say their images are tack sharp, but when you look at an image in detail you'll find it has been sharpened anyway, and sometimes sharpened too much. Any half-decent lens will be sharp or very sharp around F/5.6 for a fast prime, F/8 for a somewhat slower prime or for a zoom. The real difference comes in where a fast zoom or prime is almost as sharp wide open, or close to wide open. Well, for sharpness anyway.

There really is a point where sharpness gets overrated (and this said by someone who did quite a few sharpness tests in the past, still in the analog era, with charts and all that :D). Any L-lens f.e. is really beyond sharp enough, as are most USM lenses. It really becomes about what you do with them, rather than how sharp they are. Just don't let yourself get confused by those who are talking about super sharpness etc.

Kind regards, Wim


EOS R & EOS 5 (analog) with a gaggle of primes & 3 zooms, OM-D E-M1 Mk II & Pen-F with 10 primes, 6 zooms, 3 Metabones adapters/speedboosters​, and an accessory plague

  
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HoosierJoe
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Sep 12, 2010 16:31 |  #35

I'm in the process of that now with a new lens.

I take a picture of a stationary subject, well lit, wide open, on a tripod using a timer at low ISO.

Then I post the picture and beg POTN to tell me what they think.



Ain't nothin but a thing.

  
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HoosierJoe
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Sep 12, 2010 16:33 |  #36

wimg wrote in post #10895658 (external link)
Shoot with your lenses so that the framed image is the same size, and compare those. Preferably of a subject with plenty of detail. A brick wall with reasonably varied bricks set in rough mortar (where you can easily see the grains of sand used to make the mortar) will do.

Thsi way you can compare all of your lenses the same way. Not that the same frame is very important here (and difficult to achieve), although you can measure out a distance of, let's say, 50X the FL, to achieve this.

Also note that focusing is critical in this case, and therefor also stability. SO use a good tripod, LiveView at 10X for critical (manual) focusing, mirro lock up, and a remote switch. Count at least ten seconds between touching the camera/flipping up the mirror, before actually taking the shot. Also, take several shots at the same aperture, focused slightly different each time, and use the sharpest of the shots for comparison.

As others said, sharpness is not the be all and end all though. Often the overall rendering and pleasing bokeh is much more important. The latter two are difficult to measure, however, as they are very personal to the shootist.

As to super sharp vs sharp: many people do show a super sharp image, or say their images are tack sharp, but when you look at an image in detail you'll find it has been sharpened anyway, and sometimes sharpened too much. Any half-decent lens will be sharp or very sharp around F/5.6 for a fast prime, F/8 for a somewhat slower prime or for a zoom. The real difference comes in where a fast zoom or prime is almost as sharp wide open, or close to wide open. Well, for sharpness anyway.

There really is a point where sharpness gets overrated (and this said by someone who did quite a few sharpness tests in the past, still in the analog era, with charts and all that :D). Any L-lens f.e. is really beyond sharp enough, as are most USM lenses. It really becomes about what you do with them, rather than how sharp they are. Just don't let yourself get confused by those who are talking about super sharpness etc.

Kind regards, Wim

A lot of truth in that. I like my images reasonably sharp out of the camera. I don't like doing a whole lot of PP.



Ain't nothin but a thing.

  
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six4
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Sep 12, 2010 16:36 |  #37

Thanks Wim - a very informative post




  
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Bear ­ Dale
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Sep 12, 2010 16:36 |  #38

Chrisku13 wrote in post #10892898 (external link)
I use a process called photography, in which I go out and test the lens in various situations and come home to see if it looks alright.

+1

.


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HoosierJoe
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Sep 12, 2010 16:38 |  #39

DavidR wrote in post #10895394 (external link)
I have the same test for all lenses. My old hat, shot wide open.

And compare the images against my other lenses at a 100% crop


If it passes my test, its a keeper lens.

Except for the slightly annoying logo on the hat, this seems like a good test. Something with a Colts logo would undoubtably improve the test.



Ain't nothin but a thing.

  
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MP4/8
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Sep 12, 2010 16:49 |  #40
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yogestee wrote in post #10894394 (external link)
If you want to spend the rest of your life only photographing test charts, newsprint, batteries, brick walls etc then by all means go and shoot test charts, newsprint, batteries, brick walls etc..

Now,, if you want to step outside the box and do something really different,, go shoot a portrait, a landscape, a butterfly, your neighbour's cat or little Johnny playing football.. This is what lenses were designed to shoot..

Objective testing is the best way to determine if the copy of the lens you've got is sharp.

The OP is asking HOW to test for sharpness.

Not whether he should reconsider the 'value' of sharpness, or whether he should consider other aspects of lenses...

On topic, I've set up a controlled scene, and shot using a tripod, with timed shutter release, and tested lenses against one another, at various apertures, and done tests for back focus/front focus.

.


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twoshadows
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Sep 12, 2010 20:24 |  #41

OP,

feel free to print out the chart in my sig - 24x36 inches if you can - and fill the frame with the chart. It's what I usually use, fwiw.


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yogestee
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Sep 12, 2010 20:30 |  #42

MP4/8 wrote in post #10895802 (external link)
Objective testing is the best way to determine if the copy of the lens you've got is sharp.

The OP is asking HOW to test for sharpness.

Not whether he should reconsider the 'value' of sharpness, or whether he should consider other aspects of lenses...

On topic, I've set up a controlled scene, and shot using a tripod, with timed shutter release, and tested lenses against one another, at various apertures, and done tests for back focus/front focus.

.

I'm wondering if the OP understands the difference between outright lens sharpness and the lens' abilty to focus accurately.. Two entirely different thngs.. If one needs to test for outright lens sharpness one needs to focus manually, for the lens' ability to focus accurately, naturally one needs to use auto focus..


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DStanic
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Sep 12, 2010 20:38 |  #43

I thought I understood sharpness, but it's a funny thing. The 17-55IS is by far sharper than my Sigma 24-60 f/2.8 when used on crop. But when I use the 24-60 on my new FF camera, it's a whole new lens- very sharp wide open. I presume this is because it is using the WHOLE lens and not just 60% of it, therefore the lens as a whole must be decently sharp and in that sense not really comparable to the 17-55IS. I suspect that will be the case for various lenses- ones that are sharper in the center will excel on a crop body while another lens that may be not quite as sharp in the center but good in the mid-frame and boarders will be nicer on a full frame camera.

HoosierJoe wrote in post #10895724 (external link)
A lot of truth in that. I like my images reasonably sharp out of the camera. I don't like doing a whole lot of PP.

Very true. The first "very sharp" lens that I owned was the 70-200, I can't see why I'd ever need to sharpen an image taken with that lens, unless it was for some artistic purpose. But now virtually all of my lenses are sharp enough that sharpening is not really required (except maybe to enhance eyes or something.)


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bohdank
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Sep 12, 2010 20:52 |  #44

MP4/8 wrote in post #10895802 (external link)
Objective testing is the best way to determine if the copy of the lens you've got is sharp.

.

That will tell how sharp it is, not whether it is sharp, if you get my drift. You still have to decide what is sharp enough or to what standard you are comparing the results to. Since most higher end lenses can be described as "sharp", they are also not equally sharp. So, what is sharp enough ? A chart isn't going to tell you unless you have a lens you are using as your benchmark and if another lens is not as sharp you replace it or if it is sharper, you keep it.

Used the word "sharp" 8 times......lol


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Sep 12, 2010 20:54 |  #45

I don't test lens sharpness at all! I leave testing lens sharpness to the manufacturer.

I purchase a lens and use it and have not had a problem yet, they have all met my expectations.


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