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Konica Minolta 28-75/2.8

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bio_pawel View Drop Down
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Post Options Post Options   Quote bio_pawel Quote  Post ReplyReply Direct Link To This Post Topic: Konica Minolta 28-75/2.8
    Posted: 09 September 2020 at 15:46
Hello, it'a my first post here ;)
Just bought Konica Minolta 28-75/2.8 and given the price+description of the dealer i'am wondering weather to keep it or return it, but first i want to know weather some of the things i see are typical of this lens or are caused by wear.
Is some wobble (1-2mm) in the part that extends when zooming ok for this lens?
Is the sharpness (pictures from a68 below) at f2.8 + bit of front-focus issues from time to time when autofocusing typical for this lens or didn't my lens win the quality lottery?
28mm


~50mm


75mm



Edited by bio_pawel - 09 September 2020 at 16:02
 



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skm.sa100 View Drop Down
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Post Options Post Options   Quote skm.sa100 Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 15:51
Welcome to Dyxum, Pawel!
You might find this link helpful.

How to post images

Regards
Sashi
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bio_pawel View Drop Down
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Post Options Post Options   Quote bio_pawel Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 16:04
Thank you, I found that link before posting but messed up anyway , but it should be fine now
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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 16:15
Welcome to Dyxum Pawel

I'd be most worried about the wobble, I don't have experience with this lens but have it's shorter sister the 17-35/2.8-4D and the part that extends when zooming does not show any wobble.
When you look through the camera and wobble the part with your hand can you see the focus shift or become uneven in the viewfinder? If yes I would certainly bring it back for a free repair or a refund.

I'm not too worried about the sharpness at 2.8, it's not a high grade professional lens and secondly a design from many years ago, not much different wide open from the 17-35 and even the 28-70/2.8 G I have.

Also a bit of front/backfocus is normal and can be adjusted. Testing on a slanted plane like you showed here is not the most reliable and reproducible method. You really need to focus on something as big as the whole central AF sensor and it needs to be parallel to the image sensor and then read off the front/backfocus on a slanted surface which is besides or below the AF sensor. Also doing it at a greater distance (a few meters at least) usually gives better results than testing it really close-up like you did now.

Good luck and I hope you will get the problem solved.
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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bio_pawel View Drop Down
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Post Options Post Options   Quote bio_pawel Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 17:26
Thank you for the info, the only thing that changes when I try to wiggle the front part is the slightest shift of the entire image (pretty much only noticeable when on tripod). I guess the 17-35 does not extend that much when zooming. Maybe someone who used the 28-75 will give some info about this.
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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 17:28
I had the Tamron version of this lens and now have the Sony SAM version. My Sony is very sharp wide-open. There is not much wobble when zoomed. Out-of-focus backgrounds are very busy wide-open.

My not as sharp Tamron was sharper than all the Minolta zooms I compared it too. Your A68 allows autofocus adjustments.

I'd like a wider wide end on a full-frame camera. The DT 16-50mm F2.8 SSM is much nicer on APS-C. Or even the Tamron 17-50mm F2.8.

Wobble is pretty typical of these zooms. I have a 28-300 which is only sharp wide-open at 300mm if I support the extended barrel. It is annoying.

Edited by QuietOC - 09 September 2020 at 17:33
Sony A7III HVL-F45RM LA-EA3 LA-EA4 MB-IV MC-11 EF-E II MD-NEX KR-NEX DA-NEX
Minolta Maxxum 600si
Pentax Q7 5-15 15-45/2.8 8.5/1.9 11.5/9 AF-P/Q
 



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bio_pawel View Drop Down
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Post Options Post Options   Quote bio_pawel Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 19:35
So I guess all in all my lens in a ok condition. I know it's not a great choice for APS-C, I bought it to use it on Dynax 5 film body just did some quick test shots with the digital camera.
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addy landzaat View Drop Down
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Post Options Post Options   Quote addy landzaat Quote  Post ReplyReply Direct Link To This Post Posted: 09 September 2020 at 20:54
Focal length is personal. I find the long end of lenses like the 16-50 and 17-50 quite limiting. For years, I used a 24-85 as my main lens on APS-C. With a 16/17-50 I would have been limited on the long end. Like I said, focal length is personal.
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Post Options Post Options   Quote skm.sa100 Quote  Post ReplyReply Direct Link To This Post Posted: 11 September 2020 at 04:07
Originally posted by bio_pawel bio_pawel wrote:

So I guess all in all my lens in a ok condition. I know it's not a great choice for APS-C, I bought it to use it on Dynax 5 film body just did some quick test shots with the digital camera.


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