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03-16-2012, 01:32 PM   #1
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Foggy photo - Issue with FA 31ltd or lighting?

Hi, I decided to jump into DSLR and purchased my Kx and FA 31 ltd several months ago.

Lately when I took photo, toward the middle of the image it is somewhat foggy. This problem is most apparent when taking photo of people. I'm wondering if this is due to the lens or the lighting? Any advice would help.

Here is a family photo. If you look toward the ladies head, you will see what I'm referring to.

For this photo, I used a Metz 50 AF-1 for additional lighting.

Thanks.




03-16-2012, 02:02 PM   #2
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Are you using any filters at all on the FA31mm? if so, try not to use any filter at all. There could be smudges on the filter or the lens.
03-16-2012, 03:21 PM   #3
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@Aleonx3. No. I did not use any filter.
03-16-2012, 04:16 PM   #4
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I think you need to give it more testing (perhaps without flash) in order to determine the real issue. It is rather unusual to see the "soft" centre focus point that the edges.

03-16-2012, 05:15 PM   #5
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I'll add my .02 - it appears that the lens is front focusing?? The gentlemen on the sides are in sharp focus while the folks in the middle, who appear to be lightly behind them, are not as sharp.

Perhaps some testing using manual focus might show the problem better??
03-16-2012, 05:38 PM   #6
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Soft Spot?

Hello Mattcha, Welcome to the Forum!
After viewing the photo, my first impression was that the lens was front-focusing, so the people closer to the camera were in sharper focus.
However, look at the plaid chair in the lower right-hand corner. Seems sharp and clear, the lines of color change are crisp. This chair apprears to be much farther away from the camera than any of the people.
So, my guess is that there's some sort of smudge or mark (fingerprint?) in the center of the lens.
If the same result appears with other different photos, I would send the lens in to be checked.
You might also try other lenses on the same camera body to make sure the problem is not with the body; Perhaps a local camera store would allow you to do this, or another Pentax user.
Good Luck!
Ron
03-17-2012, 10:46 AM   #7
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Aside from the front-focusing issue (which can be corrected using AF fine adjustment), the haziness exhibited in the middle appears to be some kind of cleaning marks (or smudges) on the glass. I would use another lens and test it out to ensure it is not the camera, then I would try to see if it has the same issue without using the flash, such as take a photo outside. If you suspect the lens could be the problem, take the lens out and turn the aperture ring to wide-open, use a flash light to check if you can identify the problem.
03-17-2012, 10:59 AM   #8
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Don't forget that a smug can be on the back of the lens. High contrast (like the white sweater) and flash can make things like dirt stand out by creating veil flare.


DAZ

03-17-2012, 11:14 AM   #9
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I think, lighting, incam contrast setting and technique. First thing to observe is the wall on the right is a pretty different colour value to the same wall on the left. Ie uneven lighting. The whole shot is also a bit under. When I sort out the under in photoshop with levels the right then starts to looks a bit over. Because I assume the flash is bounced towards the right. Looks pretty good if you do that and add some contrast in photoshop, the foggyness goes. But still a bit uneven. Maybe use a wider mm flash setting. Add a bit of contrast to whatever setting you're using incam.
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03-18-2012, 02:37 AM   #10
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Hi

This, your posted image, is a crop. Therefore I cannot ascertain where in the original the hazy softness is actually located. It appears however the softness is not in the centre of the original image.

The image is too dark, the reason for this is unclear to me. Is the image under exposed ? Have you darkened it in post, too much blackpoint ? You have also oversharpened the picture it seems because there is noticeable white halo as a result. Perhaps you attempted to sharpen away the "centre softness" All this treatment will mask the the problem you are trying to present us with.

I have taken the colour cast from the picture and lightened it a bit and now the softness is more clearly I think. This aids in trying to identify what the cause could be. The spotted dress shows this most clearly. But also the gentleman to the right (as we see it) behind the lady with the spotted dress is equally showing signs of the problem.

This leads me to believe that the problem is either to be found with the lens or the camera. As previously stated above check the lens for a presents of haziness (this could be an absolutely minor amount which under flashlight conditions gets magnified). If the lens glass is clear, I would check the camera. Here it is possible the sensor has suffered a certain "dullness" in one spot by way of unfavorable condensation condition. Did you take the camera in and out of tropical conditions at one stage ? Freezing then warm temperature exchanges perhaps ? Have you been "mouth blowing" the sensor ? There are many situations why a sensor can develop a localized dull spot so fine it is not noticeable at a glance even if it appears to be looking fine. I guess to be totally sure you could do a wet sensor clean.

Greetings

Last edited by Schraubstock; 09-16-2012 at 05:32 PM.
03-18-2012, 09:09 AM   #11
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It also happens to my shots when my subject wears white and my flash's bounce is either too strong or i put the light too near.
03-18-2012, 10:34 AM   #12
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ive the same issue with other lenses when there is a bright subject bouncing light back as Alizarine stated. Given that white jacket is in essence a reflector pointed back at you, this appears to account for your loss of contrast. i doubt there is any smudge on the element but definitely rule that out as well.
good luck.
03-18-2012, 10:48 PM   #13
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Hi

Of course there could be another reason for this. As I understand the FA 1:1.8 31mm AL Limited was designed for use with film SLR cameras and is not optimised for DSLRs, meaning the glass facing the sensor is not specially coated to combat the reflective sensor surface. Thus under adverse conditions as one may encounter when using a flash there could be reflections bouncing back and forth between the back lens element and sensor surface.

Extensive testing under controlled conditions would be required to verify this. But even unscientific casual testing could give you a clue.

Greetings
03-20-2012, 07:48 PM   #14
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Everyone, thank you much for the advices and potential issues. I will definitely check the lens and perform additional testings.

Thanks.
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