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05-13-2015, 07:15 PM   #1
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DA645 25mm AL - please let me know your experience.

Recently had my (almost virgin) 25mmDA return from repair. The lens had a 2-3 stop exposure divergence from f4-f32 (becoming consistently more overexposed).

Just tested it again and it's still happening.

If you own this lens, could you please report your experience by setting your 645 (z or d) to manual.

Start at f4 (select relevant shutter) and take a frame. Then go up an aperture and down a shutter speed, all the way to f32. Then report how even yr exposures are throughout the range.

Thanks, Rob

05-13-2015, 07:47 PM   #2
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When I tested the lens it was consistent, except the wider apertures were a bit darker due to vignetting, of course. Definitely no overexposure.

I've had it happen with a few K-mount lenses, though. Could be that the fault in the aperture mechanism wasn't actually repaired...

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05-13-2015, 08:13 PM   #3
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QuoteOriginally posted by rob8888 Quote
Recently had my (almost virgin) 25mmDA return from repair. The lens had a 2-3 stop exposure divergence from f4-f32 (becoming consistently more overexposed).

Just tested it again and it's still happening.

If you own this lens, could you please report your experience by setting your 645 (z or d) to manual.

Start at f4 (select relevant shutter) and take a frame. Then go up an aperture and down a shutter speed, all the way to f32. Then report how even yr exposures are throughout the range.

Thanks, Rob
Hi Rob,


Did they say exactly what they repaired? I have the lens also recently back from repair for Severe Barrel Movement , which was fixed but then returned with non working AF. Now I have it again and all is good. I haven't checked as finely as you for exposure variances with the lens, but from general shooting its all working okay. If I get a chance through the week ill have a look at it.
05-14-2015, 06:09 AM   #4
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Hi Thomas. Yes, they said they replaced the PC board in it. Nothing about the aperture itself. Rob

05-14-2015, 10:16 AM   #5
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Mine seems fine, however I have not done detailed analyses like you request.
05-14-2015, 01:43 PM   #6
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I forgot to say that it takes about 1minute to do. Just flick through the images on the playback screen and you will immediately see the issue.

Also, just saying your lens seems fine without trying doesn't really help. I had no idea either until I tried it.
05-17-2015, 12:42 PM   #7
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Disappointed I can't get anyone's help on this quick request - it's literally 1 minute of your time and would cast light onto a problem potentially affecting others.
05-17-2015, 01:03 PM   #8
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I have two and none has an issue of that sort that you describe.

05-17-2015, 01:04 PM   #9
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Thank you for trying it out.
05-17-2015, 01:04 PM   #10
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One of mine has more play in the manual focus ring than I would like though.

Last edited by Lacunapratum; 05-17-2015 at 05:49 PM.
05-17-2015, 03:32 PM   #11
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i'll play. gimme a bit to go pull out gear and will get back to you
05-17-2015, 04:50 PM   #12
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ok, i did the test (D FA version) and it maintains exposure with no detectable deviation except at f/4 which shows some vignetting.
I did the test your way...starting at f/4 and increasing shutter one stop for every aperture stop closed, up to f/22.
Then I started at f/8, established proper exposure then used AE-L and worked up and down the aperture settings...the camera also maintained proper exposure throughout.
Something is definitely wrong with your equipment.
good luck.
05-18-2015, 12:15 AM   #13
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Thank you very much Mike, that's very kind of you. Yes, the vignetting wide open is real, but the exposure wander of several stops is not. I wonder what they did in Japan for 3 months? Not happy, I've only used it a few times since new. Thanks, Rob
05-18-2015, 08:38 AM   #14
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QuoteOriginally posted by rob8888 Quote
Thank you very much Mike, that's very kind of you. Yes, the vignetting wide open is real, but the exposure wander of several stops is not. I wonder what they did in Japan for 3 months? Not happy, I've only used it a few times since new. Thanks, Rob
you should ask for a warranty replacement.
05-18-2015, 11:46 PM   #15
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QuoteOriginally posted by mikeSF Quote
you should ask for a warranty replacement.

Problem is they're a discontinued line now. The suggestion is a 28-45mm, but it's a major commitment for wilderness photography (which may involve 10 days or more lugging). That would push me back my old Canon kit which I don't want to do!
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