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05-19-2009, 08:00 PM   #1
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SMC-F 50mm/1.7 Overexposing all shots

hi everyone,

I had a chance to go to a Audi/Porsche dealership grand opening today and was excited to tale my ist dL with me. I brought the SMC-F 50mm/1.7 with me to gain some speed for indoor and evening shots. Well, I got home and loaded up the pics into Capture One Pro and found that almost all the shots were overexposed and washed out. Capture One Pro has a wizard that corrects exposure issues automatically so I tried it on all the shots to see if there's some sort of pattern with all these pics. It appears that a majority of shots overexposed by 1.3-1.5

Note; For wide angle stuff I use the stock 18-55 lens and exposure is always correct. I didn't have it with me at this event so I couldn't compare shots at the same venue.

I've posted a couple of samples on flickr. Can someone assist me in troubleshooting the problem?

50mm-overexposure - a set on Flickr

Thanks,
Ben

05-19-2009, 08:52 PM   #2
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Those are nice pictures! But as far as I can tell from the few samples posted, you're just seeing the flip side of the same phenomenon that causes many people to report underexposure - the camera is aiming for an average luminance of a little darker than an 18% gray card. If you shoot a white object, that's clearly going to lead to underexposure as it renders the white car gray, but if you shoot a black car, as you have here, that's going to lead to overexposure as it renders the black car gray. You don't see this so much in wider angles because there is usually more "stuff" in the shot to help even things out, but if the shot is dominanted by somthing white or black, you'll generally see underexposure and overexposure respective (as compared with what you'd presumably have wanted).

It's certainly possible there is more going on than this, but that seems to be pretty clearly going on in the black car shots.
05-19-2009, 09:14 PM   #3
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Thanks for the quick reply.

I'll post some shots of a silver Audi R8 that I believe were overexposed as well.

What's weird is that they appear to be overexposed when I open them up in Capture One. The pics when viewed via the LCD on the camera are colorful/vibrant and not overexposed. Again, this phenomenon only appears to be happening with my 50mm and not the 18-55 kit lens.
05-19-2009, 09:31 PM   #4
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Are you using the histogram while you shoot? With it, you're able to see if the image is washed out.

05-20-2009, 02:44 AM   #5
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I would also add that with high contrast scenes like you are shooting, YOU are the one that needs to decide how the picture should look. The "auto-exposure" wizard on your software has not got a clue in these situations and certainly are not producing "correctly exposed" images.

Your initial images may be a bit overexposed, but are in my view better than the wizards attempts
05-20-2009, 03:23 AM   #6
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not that i am qualified to judge..

but the ones you class as over exposed on my monitor look ok maybe slightly bright but none more than if they were taken outdoors..

the corrected ones look underexposed! but hey.. thats me

Thanks

Steve
05-20-2009, 05:53 AM   #7
pdo
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I had the 50mm F1.7 and it sometimes overexpose. Then I found out there's oil on the aperture blades so it doesn't close properly.
05-20-2009, 07:35 AM   #8
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Thanks for all the replies.

I'm going to take a look at the histograms when I get home. I did take a look at some of the histograms when I was shooting and did notice that some of the washed out shots were not evenly distributed but had peakson the right hand side of the histogram.

I'll take a look at those shots on my work monitor and see if they look any different. Maybe my Dell Inspiron 1420 laptop with the glossy screen is the problem.

05-20-2009, 03:54 PM   #9
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I had a look at the TTS picture. The only blown highlight is the silver TT lettering. The white paintwork is not overexposed at all. I do think that the white balance is off however.

I have taken the liberty of downloading your picture; altering the white balance; correcting the blown highlights (not that it really matters for this picture in my opinion); and sharpening it up.

What do you think ?

05-20-2009, 08:01 PM   #10
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Looks great I can see how there is more detail in the first "T".

I looked over the photos again and found that they were not that bad. My screen at work is much better suited for photo viewing versus my glossy laptop screen.

After going out with the 50mm I've found that it made me think more about composition versus going out with the 18-55 and just blasting away. I still have a lot to learn, but thank you to all who replied.

Here are some more photos for all to enjoy. The Mercedes SL65 Black Series was quite a sight. Only 200(?) in the US.

Burlington Audi/Porsche - a set on Flickr
05-21-2009, 09:30 AM   #11
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QuoteOriginally posted by pdo Quote
I had the 50mm F1.7 and it sometimes overexpose. Then I found out there's oil on the aperture blades so it doesn't close properly.
That was my first thought, a possible mechanical issue with the lens. The aperture blades are held open for composing, then have to rapidly stop down to your chosen setting when the shutter is pressed. You might notice more overexposure at f22 because the blades have to move the farthest.

I would try some shots with the DA 18-55 set at 50mm, then the same shot with the F50/1.7 with the same settings and light. A tripod would make this easier. The exposures might not be exactly identical, but ought to be within 0.3 stops of each other.
05-22-2009, 04:48 AM   #12
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No overexposure on my screen either. They are on the edge however. This is why I generaly underexpose in these critical situations. Because it's easier to recover a underexposed image, you keep the detail. Overexposure is just not possible to repair.
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