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| Question on Minolta 24-85mm sharpness; is mine faulty? | |
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| Tweet Topic Started: Apr 9 2008, 09:21 AM (1,037 Views) | |
| weishengg | Apr 9 2008, 09:21 AM Post #1 |
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Alpha Elite Member
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Hi all, recently i just purchased a secondhand Minolta 24-85mm f/3.5-4.5 lens for my Alpha A100. When I got home and did my amateurish pixel peeping at some pictures i shot on my way home, i realized that the lens is either not focusing properly, or badly lacks sharpness at certain apertures. I hope to seek advice from fellow forum members on what to do with regards to this. Let me just highlight the problem first. here are 2 test shots i did, camera tripod mounted, autofocused and focal length held. cropped >100% at the centre of the frame where it was autofocused at. first one at 24mm f/3.5 second one at 24mm f/7.1 Another test set at 85mm, same procedure. First one at 85mm f/4.5 Cropped image in centre Second one at 85mm f/7.1 Cropped image in centre Here are a few more test shots. Shot many many times and I'm pretty confident its not a matter of not autofocusing correctly. Its autofocus is quite consistent as far as I am able to detect. 1st set: 85mm, 1/125sec, f/4.5, ISO400, Flash fired Centre cropped 2nd set: 85mm, 1/125sec, f/7.1, ISO400, Flash fired Centre cropped I am not very satisfied with this lens, but I just want to know if this is an inherent inferiority of the lens or had it been damaged and is still repairable? what do you think? |
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weishengg.blogspot.com Snap away! | |
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| weishengg | Apr 9 2008, 09:24 AM Post #2 |
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Alpha Elite Member
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anyway apologies, i should have kept the exposure value of the towel test shots consistent. but i dont think it'll affect the sharpness of the image right? |
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weishengg.blogspot.com Snap away! | |
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| Ming | Apr 9 2008, 09:48 AM Post #3 |
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90609866
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Did you try shooting outdoor ?
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Ask ... Absorb ... Equip ... Execute N E X with M I N G HERE ! A P - Ming HERE ! Macro-Ming HERE ! Pano-Ming HERE ! Food ! Food ! Foods ! HERE | |
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| weishengg | Apr 9 2008, 10:02 AM Post #4 |
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Alpha Elite Member
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oh not yet, but should i expect to see any difference? will take it out to shoot some pictures and examine again. |
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weishengg.blogspot.com Snap away! | |
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| Stvc | Apr 9 2008, 08:04 PM Post #5 |
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Newbie
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Did you turn off your SSS when you mount on tripod? |
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My Flickr | |
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| Tomato | Apr 9 2008, 08:13 PM Post #6 |
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Forum Advisor
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f4.5 is the widest aperture, some consumer grade lens aren't going to be as sharp wide open. f7.1 is probably good for sharpness for this lens. Though, my version is sharp at f5.6 onward. Regards, Hart |
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Qualified Master Photographer | Certified Premier Greener Photography Tomato Photo Website | Bambini Photography Website | Tomato on Facebook | |
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| bulldog | Apr 9 2008, 08:32 PM Post #7 |
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Alpha Commander Member
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hi, ya.. agreed with hart.. when i open the aperature wide for shooting my spiders.. only the centre part or the head is sharp.. then when i down the aperature to F8 or higher, all seems clearer.. also today when shooting the IR @ LP.. i thought i open the widest so can shorten the explorsure time... result.. very blurr... close the aperature to F8 above.. all so clear again... |
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Darren Chin a.k.a Alpha-Bulldog... A550 18-55mm Kit Lens | |
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| jasahchun | Apr 9 2008, 09:21 PM Post #8 |
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路人甲
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bro.. what you say is the depth of field.. aka bokeh.. sharpness in consumer glass that hart is talking about is different..
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| bulldog | Apr 9 2008, 09:27 PM Post #9 |
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Alpha Commander Member
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hi, oh.. DOF.... |
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Darren Chin a.k.a Alpha-Bulldog... A550 18-55mm Kit Lens | |
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| jasahchun | Apr 9 2008, 09:31 PM Post #10 |
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路人甲
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ya.. do take a zoom glass out of your fridge.. just shoot normal staffs at different aperture.. you will see the differences in sharpness.. i got Tamron 17-50mm F2.8, but it's sharpest is around F4 onwards woh.. |
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