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Another Rokkor 58mm f/1.2 to Minolta AF conversion

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hotwire View Drop Down
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Post Options Post Options   Quote hotwire Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 04:11
Stop down metering by definition is completely manual... in other words you are the one to stop down the lens.

Short summary of steps:
Turn lens detection off (aka shutter open with no lens attached)
Set to Aperture priority
Turn off AS/SSS

Open lens wide open
Focus
Close the aperture manually to your desired aperture
Press shutter.
Repeat
a99ii; Maxxum 9

CZ: 16-35, 24-70/2.8, 135/1.8; Minolta: 50/1.4; MC58/1.2; 85/1.4GD 300/2.8; 500/8; 600/4; Tam: 90/2.8M; Sig: 12-24/4.5-5.6; 15/2.8; Sony: 35/1.4G; 135STF, 70-200/2.8G
 



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beline View Drop Down
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Post Options Post Options   Quote beline Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 04:16
so, tripod-only shooting then eh?

not very practical for anything other that macro or very intentional portraiture...

from the looks of things... doesn't seem like infinity is a mush with an old MD/MC... for portraiture or still life anyway. also, seems like the added distance might make the lens a bit of a macro...

Edited by beline - 20 October 2007 at 04:18
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Arkku View Drop Down
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Post Options Post Options   Quote Arkku Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 12:10
Why would this mean tripod only?

Image stabilisation doesn't work (without an electric adapter), granted, but none of the 35mm pro cameras ever had image stabilisation in the body.

Anyhow, you can use either A or M mode with the manual lenses (this or M42 or whatever). The only difference between the regular A and M modes is that you set the aperture by turning a ring on the lens instead of a dial on the camera. The lens stops down immediately once you turn the ring, so generally you will first wish to focus wide open (manually, of course) and only then turn the ring to stop down, but this is only a problem for moving targets (which are ill-suited for manual focus anyhow).

As for the infinity focus, my guide to the modification has instructions on how to adjust the infinity focus to match. Actually it's easy to get it going past infinity, the time-consuming part is trying to get it just right without limiting the maximum distance. So, non-perfectionists can just crank it a bit past infinity and sacrifice a bit of macro range.

Edited by Arkku - 20 October 2007 at 12:12
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Turerkan View Drop Down
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Post Options Post Options   Quote Turerkan Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 14:45
you can focus stopped down too, especially when there is enough light.
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Post Options Post Options   Quote beline Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 20:04
the reason I say you'd need a tripod, is because if you are doing hand-held at close distances, the movement after the focus while you stop-down will throw you focus off (did that make any sense?).

you could focus stopped down, but the extra depth of field would make accurate focus slightly more difficult for some of us.

anyway, the reason I would be interested in M42 and old MD/MC lenses, as I don't currently own any, would be the (aperture + glass quality)/Cost ratio. wide open aperture, with a razor-thin DOF, and razor-sharp image, is a beautiful thing...
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Turerkan View Drop Down
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Post Options Post Options   Quote Turerkan Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 21:15
as the aperture decreases, required focusing acurracy also decreases.. for this reason i find myself using DOF preview when i'm at close distances, this way i don't have to go super-precise, i can see the actual DOF and act accordingly.

overall, imho stop down focusing is good for close up photography, provided that there is enough light to focus.. you don't try to shoot macros at night anyway, do you?..
 



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Arkku View Drop Down
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Post Options Post Options   Quote Arkku Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 23:11
Originally posted by beline beline wrote:

the reason I say you'd need a tripod, is because if you are doing hand-held at close distances, the movement after the focus while you stop-down will throw you focus off (did that make any sense?).


Well, I don't usually shoot very close distances with these lenses (everything focuses to infinity just fine), but with close-up and macro work I would use a tripod regardless of the lens (need to stop down for depth of field, increasing exposure time at my preferred ISO 100). For longer distances it's really not that sensitive with the focus, plus you don't need to move the camera away from your eye to stop down (count the clicks on the ring or just stop down until it the DoF looks about right).

Also, like Turerkan said above, if there's enough light, one can focus stopped down. With the increased DoF it's seldom problematic, and in bright light it's quite easy to tell where the point of focus is by looking at the edges of details in the area.
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edrice View Drop Down
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Post Options Post Options   Quote edrice Quote  Post ReplyReply Direct Link To This Post Posted: 20 October 2007 at 23:39
Here's one I did some time ago with my A100 and the 58mm f1.2. This was shot at wide open. Notice that the depth a field is so narrow the clapper is in focus but the flange on the bell is bit blurry, front and rear.



BTW, it's news to me that one should turn off anti-shake with this lens. All the shooting I've done was with it turned on, inlcuding this one, and I haven't noticed any problems. Matter of fact, I thought I'd still get a degree of anti-shake, though not as much. Seemed to work for me. I've never embarrassed my A100 by hanging a tripod from its underments.

Ed

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Pete Ganzel View Drop Down
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Post Options Post Options   Quote Pete Ganzel Quote  Post ReplyReply Direct Link To This Post Posted: 21 October 2007 at 09:45
I'm with you Ed.

AS (or SS) seems to work to some extent without lens information, at least in this mid focal length range. I never shut it off. My entire 58mm Rokkor gallery was shot with AS on,hand held and wide open at f/1.2. The only images showing unsharpness are because of my careless focus.

Beline: There are lenses in AF mount which are four stops slower than the f/1.2 wide open and folks have no problem focusing with them.
BTW, why would you use this lens stopped down more than a stop or so? There are automatic iris, meter coupled, AF lenses that are probably better for that use.

As Ed mentioned, the area in focus is very thin wide open at f/1.2.
Here's a little chart done with calculations and testing showing what you are working with, but as you say, that's part of the charm of   these lenses.




Pete





Edited by Pete Ganzel - 21 October 2007 at 09:50
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teko View Drop Down
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Post Options Post Options   Quote teko Quote  Post ReplyReply Direct Link To This Post Posted: 22 October 2007 at 08:12
Hi Guys,
Just want to tell you all Iíve done the same conversion for my 58/1.2.
Tribute goes to Pete and Arkku for their inspiration.
Pete in his homage said the thickness of the mount should be 7.75-8mm thick, and that gives me the idea of making the spacer myself, and plastic would be the most readily available and easiest material to handle.

So what I did is instead of filing the mount spacer, I took the whole part out and use a piece of plastic that I use for model making (about 1mm thick) and trim it to the size of the mount spacer. I then use that piece of plastic to act as the spacer and mount the M42 adapter to the lens, and thatís it, and I donít even have to adjust infinity. In fact, infinity focus at the 30 ft mark but thatís good enough for me.

One more thing, the M42 adapter has to be filed a little bit, cos the lens aperture linkage will be jammed when you adjust the aperture.

Hereís a picture I took wide open, hope you guys will like it.

Rokkor%2058/1.2

Edited by teko - 22 October 2007 at 08:31
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terryg View Drop Down
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Post Options Post Options   Quote terryg Quote  Post ReplyReply Direct Link To This Post Posted: 22 October 2007 at 12:03
I like it!

Terry
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Post Options Post Options   Quote Sanjuro Quote  Post ReplyReply Direct Link To This Post Posted: 29 October 2007 at 15:17
Originally posted by terryg terryg wrote:

I like it!

Terry


Indeed!
a 58/1.2 hmmm
Rgds
Sanjuro

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Post Options Post Options   Quote ricardovaste Quote  Post ReplyReply Direct Link To This Post Posted: 09 November 2007 at 13:45
Would there be anything to stop someone *cough*me one day, maybe* successfully attempting to do a complete rokkor line up into a AF conversion?

20/2.8, 24/2.8, 28/2, 35/2.8, 85/2, 100/4 macro

All done by fiddling with the mount and adding a m42~af adapter?

Or would it not work for all lenses...??
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Arkku View Drop Down
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Post Options Post Options   Quote Arkku Quote  Post ReplyReply Direct Link To This Post Posted: 09 November 2007 at 19:55
There isn't a theoretical reason why it wouldn't work, but the adjustability of individual lenses may vary, i.e. some may be more difficult to disassemble and/or have less opportunity for getting infinity focus right. Of course, other tactics may then be applied, with some creativity. =)

Personally I don't feel that all of the old Rokkors are so desirable over M42 alternatives that I'd bother going for a complete line-up. But, of course, if you already have the lenses and like them, why not go for it and post the results here? =)
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