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03-22-2013, 05:53 PM   #1
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F 50 1.7 not sharp over 13 ft away

I don't know what I'm doing wrong. Am I expecting too much? My images are sharp unless I'm over about 13 feet. Then, not so much. Is that typical for this lens? I'm putting a flickr link so you can see what I mean. At 100% crop there is a definite difference.
I'm shooting with a Kr, would a different camera make a difference? I'm hoping to upgrade to the K5 soonish .
Thanks for your help!
distance test - a set on Flickr

03-22-2013, 06:08 PM   #2
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Well, lets eliminate some stuff first...
Have you tried manually focusing in live view?

PS : I'd like to say that i faced many, many problems with my F 50mm 1.7, but i guess i finally fixed it last week...here are some 100% crops with it. I took them right now for this thread, so i had to use my tripod, but with SR OFF and remote shutter release.


Both at f2. Converted from raw, with my default camera raw settings. The camera was a K-30.

Last edited by GabrielFFontes; 03-22-2013 at 06:18 PM.
03-22-2013, 06:18 PM   #3
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I never use it in live view. I did have it in multipoint focus and wonder if that may be part of the problem. I switched it, hopefully that will help.
03-22-2013, 06:21 PM   #4
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How did you fix yours?

03-22-2013, 08:10 PM   #5
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QuoteOriginally posted by April.H Quote
I don't know what I'm doing wrong. Am I expecting too much? My images are sharp unless I'm over about 13 feet. Then, not so much. Is that typical for this lens? I'm putting a flickr link so you can see what I mean. At 100% crop there is a definite difference.
I'm shooting with a Kr, would a different camera make a difference? I'm hoping to upgrade to the K5 soonish .
Thanks for your help!
distance test - a set on Flickr
It's not easy to see exactly what the camera has focused on. Can you try focusing on a flatter subject? At f/1.7, not all those wooden items in the shot will be in focus because the depth of field is so shallow. Try focusing on a distant row of buildings. That would be a better test, as long as the conditions are clear.

I have an FA50/1.7 that would not focus on distant subjects when I bought it, because (I assume) someone had opened it up to clean it, and on reassembly wrongly adjusted the focusing ring. It wouldn't turn far enough to achieve infinity. Easily fixed by someone who knows how to do it. Now it's fine. (Although prior to that, two professional lens repairers gave me a lot of BS about it not being faulty, oh the lens was not built for digital, and all the cr*p). Also, at f/1.7 accurate focus is critical. A lot of complaints about the softness of 50mm lenses wide open is related to slight misfocusing, I am convinced.

If there is a problem it is likely to be that your camera is slightly misfocusing (and a K5 enables you to adjust that for individual lenses), or the lens needs a bit of internal adjustment, or you are simply focusing on the wrong thing within the picture. All are possible. Don't test it on multipoint focus - who knows what the camera selected?
03-22-2013, 08:14 PM - 1 Like   #6
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1/ You are shooting wide open at f1.7 ( very narrow DOF )
2/ The camera is focusing on the highest contrast item , that is the well and not the Dial. It can't read your mind, so use either the center spot focus
or select the point you want.
Multipoint focus is good to catch something moving like birds in the open sky.
If you had set the F stop to 5.6 or higher it would have worked .
03-23-2013, 01:13 AM   #7
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What exactly is wrong with your lens? I can see nothing out of order. You are shooting wide open, so you should expect limited depth of field (few things in focus). Also, sharpness wide open is better for close rather than distant subjects. You have to close the aperture more for those.
03-23-2013, 04:37 AM   #8
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It looks like it's just misfocusing. Try centre point focus as others have suggested, focus specifically on the wheel thing, and then try your tests again.

I see nothing that is wrong. Extreme pixel peeping might reveal something, but then I think you're asking for too much. If anything, it is with your camera body.

I love my F 50 1.7. It's probably the last lens I will ever part with. If I got results like what you are getting, I would not be troubled in the slightest.

Stop worrying. Get out there and shoot.

03-23-2013, 08:29 AM   #9
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QuoteOriginally posted by EarlVonTapia Quote
It looks like it's just misfocusing. Try centre point focus as others have suggested, focus specifically on the wheel thing, and then try your tests again.

I see nothing that is wrong. Extreme pixel peeping might reveal something, but then I think you're asking for too much. If anything, it is with your camera body.

I love my F 50 1.7. It's probably the last lens I will ever part with. If I got results like what you are getting, I would not be troubled in the slightest.

Stop worrying. Get out there and shoot.
I don't know what you mean...
Yeah, i'm a darned pixel peeper, but c'mon!
That picture is so out of focus, it could have been manually focused by my 5 year old cousin.
The picture, even reduced, would trouble me without a single piece of doubt.
I think OP should try liveview focusing to check for focusing problems...
03-23-2013, 08:38 AM   #10
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QuoteOriginally posted by kcobain1992 Quote
What exactly is wrong with your lens? I can see nothing out of order. You are shooting wide open, so you should expect limited depth of field (few things in focus). Also, sharpness wide open is better for close rather than distant subjects. You have to close the aperture more for those.
You can see from my pictures (and i'm using a 16 MP sensor, he is using a 12 MP one) that there is something wrong with his lens, or with his focusing technique (he isn't using center point to focus, so he isn't sure if the camera chose the wrong focus point).
His picture are really, really soft...but i'm sure he will be able to fix it, it doesn't seem like a big problem.
This lens at f2 is already sharp.
03-23-2013, 12:22 PM   #11
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I'll stand by my initial point that I see nothing wrong with that lens.

To the O[riginal]P[oster], I don't know how much effort you want to put into squeezing an extra .05% of sharpness wide open out of a $200 lens and an old DSLR body.

Seriously, your pictures look about right for what the lens can do given the conditions.

Try center point focus, aim it a the dial, and see if you're still getting "bad" results.

Again, if I got the results you are getting, I would not be troubled in the slightest.
03-23-2013, 12:36 PM   #12
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QuoteOriginally posted by EarlVonTapia Quote
I'll stand by my initial point that I see nothing wrong with that lens.

To the O[riginal]P[oster], I don't know how much effort you want to put into squeezing an extra .05% of sharpness wide open out of a $200 lens and an old DSLR body.

Seriously, your pictures look about right for what the lens can do given the conditions.

Try center point focus, aim it a the dial, and see if you're still getting "bad" results.

Again, if I got the results you are getting, I would not be troubled in the slightest.
Earl, do you think that this

is 0.5% sharper than this

?
But OP doesn't seem to be answering anymore, so we can't really help...
03-23-2013, 12:44 PM   #13
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QuoteOriginally posted by GabrielFFontes Quote
Earl, do you think that this

is 0.5% sharper than this

?
But OP doesn't seem to be answering anymore, so we can't really help...

I stated before that it's misfocusing due to multi-point AF. It seems to be focusing on the roof above the dial. Thus my suggestion to try center point AF and aim it right on the dial to see if she's still getting those results.

And what would you suggest as a fix? Open it up like you do with your bodies and lenses? Is that really worth it for an F 50 1.7?

In the off chance there is actually something wrong with the lens, she should just chalk it up to a bad copy and get another one through the marketplace. They pop up all the time.
03-23-2013, 12:51 PM   #14
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Yeah, it does seem like a multi point AF problem...as the subject gets smaller, the camera gets confused...
Anyway, i do like opening my lenses and tweaking them, and i do think its worth it for a F 50mm 1.7 : it's a great lens!
03-23-2013, 01:29 PM   #15
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QuoteOriginally posted by EarlVonTapia Quote
And what would you suggest as a fix? Open it up like you do with your bodies and lenses? Is that really worth it for an F 50 1.7?
I agree with you that the more likely issue is that AF has decided to focus somewhere else, not where the OP wanted. Depth of field at 13 feet, 50mm and f1.7 is about 8-10 inches.

There really is only one adjustment on the lens. A couple of years ago, someone here had an F50/1.7 that couldn't focus to infinity, and that's not too hard to fix with a JIS screwdriver. Focus to minimum distance. Remove three screws on the front barrel, slide that off. Focus back to the other end of the scale. Loosen the three recessed screws now-visible screws around the front element. Now you can move the focus ring slightly away from infinity without changing the lens's actual focus. Move it a bit, tighten one screw, then try to focus to infinity. Repeat until it focuses to infinity, tighten all the screws, reinstall the barrel.

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