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Old Apr 6, 2011, 6:27 PM   #1
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Default Comparing f1.8 v. f2.2 on my new ef 85mm f1.8 USM

I recently purchased a new ef 85mm f1.8 USM to use for courtside, indoor sports action (basketball, volleyball, etc.). I haven't had a real opportunity to use it in a gym but I have played around with it. I'm trying to determine sharpness and I've posted a couple of pics of my GSP running in the backyard in full shade, the first at f1.8 & the second at f2.2, cropped, with no post processing. To me, the f2.2 is much sharper, but I'd like to get other opinions.

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Old Apr 6, 2011, 7:31 PM   #2
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It's not unexpected for 2.2 to be sharper than 1.8. However, this lens is plenty sharp wide-open at 1.8, or most copies are. In the first picture, its difficult to tell but it looks like the focus is a bit off possibly, whereas in picture #2 it seems better centered around the face.

I would like to see this test with a static subject. if you can have your dog sit for a bit, make sure you get a good lock on the eyes and do a test at 1.8, 2.2, 2.8, or whatever apertures you are interested in, i think we could at least take the focus variable out.
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Old Apr 6, 2011, 7:33 PM   #3
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There are a couple of things going on. First, yes, that lens does get a little bit sharper as you stop down. Second, as you stop down, you get a little bit more depth of field, so more of the image is sharp.

But when shooting indoor sports, you may find that you need all the aperture you can get. You'll also be capturing subjects that are further away from you than your dog was in those shots, so you'll get a little more depth of field anyway.

I suggest you start off at f/1.8 and ISO 200, and see what shutter speed you can get. If you can get 1/400 or better, stop down a little (to increase sharpness) and increase the ISO a little so you still get the same shutter speed.
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Old Apr 6, 2011, 7:47 PM   #4
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Quote:
Originally Posted by Hards80 View Post
It's not unexpected for 2.2 to be sharper than 1.8. However, this lens is plenty sharp wide-open at 1.8, or most copies are. In the first picture, its difficult to tell but it looks like the focus is a bit off possibly, whereas in picture #2 it seems better centered around the face.

I would like to see this test with a static subject. if you can have your dog sit for a bit, make sure you get a good lock on the eyes and do a test at 1.8, 2.2, 2.8, or whatever apertures you are interested in, i think we could at least take the focus variable out.
I was thinking the first might have a slight focus issue as well. I'll try a couple of stills as suggested for better comparison.
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Old Apr 7, 2011, 5:15 AM   #5
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Just for the heck of it, you might try this: http://www.focustestchart.com/
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Old Apr 8, 2011, 7:16 AM   #6
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As suggested, I took some shots with Daisy (my GSP) sitting still. I was amazed how sharp this lens remains wide open at f1.8. I didn't spend a lot of time on the picture composition, just checked exposure, adjusted sensitivity, and had the dog sit & released the shutter. You can see the slight difference in depth of field from 1.8 to 2.2. I also should adjusted sensitivity for the second pic, it's a little underexposed at ISO 50. After these, I took one at f3.2 and was delighted by how sharp the lens was as it was stopped down. I think, for the money, this lens is very hard to beat. Pic 1 is 1.8, 2 is 2.2.
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Old Apr 8, 2011, 7:33 AM   #7
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Jerry,
For what it's worth I operate mine at 2.0 - that 1/3 stop really seems to help the sharpness from 1.8:
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Old Apr 8, 2011, 7:44 AM   #8
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Jerry,

Congratulations on the new lens. Looks liek it is working very well on the last two shots of Daisy.

John,
Nice illustration of shaprness and shallow DOF with your son there.
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Old Apr 8, 2011, 12:40 PM   #9
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Jerry,
For what it's worth I operate mine at 2.0 - that 1/3 stop really seems to help the sharpness from 1.8:
Coming from you, it's documented and will be my initial setting when I get in the gym. I think you get some great pics and you were the first one to recommend this lens to me in the first place.
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