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M42->MAF Adapter With Focus Confirmation

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revdocjim View Drop Down
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Post Options Post Options   Quote revdocjim Quote  Post ReplyReply Direct Link To This Post Posted: 10 April 2008 at 13:51
You may be right Arkku. I don't fully understand this stuff so I guess I just instinctively play by the rules.

On another topic, just this evening I discovered a weird problem. I've always left the camera aperture setting at the max when using the James Lao adapter. I decided to try the other method described on the first page of this post, that allows you to have correct exif data. Here's what happened:

I had the camera set for the correct data set. I framed the picture, set aperture on camera to f/2.8 (on the f/1.4 lens), focused, pushed the AEL button. Set the aperture on the lens to f/2.8. Released the shutter. I got an error every time. I tried various things and found that regardless of the AEL button, any time I stopped down the camera aperture setting beyond a certain point I would get an error upon shutter release.

Camera: A700
Lens: 50/1.4 If I set the aperture on the camera to f/2 or smaller taking a picture makes the body lock up with an error. I have to power down the camera to get it going again and the recorded frame is black. The camera also makes a weird, almost chirping sound when trying to take the picture.

Lens: 135/3.5 Same thing. f/4 is okay but f/4.5 and smaller cause an error.

Lens: 28/3.5 Same thing but at a somewhat higher f-stop.

I thought it might be a camera problem with slow shutter speeds but nothing similar happens when I attach an AF lens.

I tried my M42 lenses with a generic, non-electronic adapter and although I can't set any aperture value I tried various shutter speeds and no problem.

Anyone know what this is...



Edited by revdocjim - 10 April 2008 at 13:54
Gallery A7S, Batis 18/2.8, 25/2 Sony 35/2.8, 55/1.8, 90/2.8M, Minolta 135STF, 200/2.8 Blog
 



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JamesLaoT View Drop Down
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Post Options Post Options   Quote JamesLaoT Quote  Post ReplyReply Direct Link To This Post Posted: 10 April 2008 at 15:22
Originally posted by revdocjim revdocjim wrote:

You may be right Arkku. I don't fully understand this stuff so I guess I just instinctively play by the rules.

On another topic, just this evening I discovered a weird problem. I've always left the camera aperture setting at the max when using the James Lao adapter. I decided to try the other method described on the first page of this post, that allows you to have correct exif data. Here's what happened:

I had the camera set for the correct data set. I framed the picture, set aperture on camera to f/2.8 (on the f/1.4 lens), focused, pushed the AEL button. Set the aperture on the lens to f/2.8. Released the shutter. I got an error every time. I tried various things and found that regardless of the AEL button, any time I stopped down the camera aperture setting beyond a certain point I would get an error upon shutter release.

Camera: A700
Lens: 50/1.4 If I set the aperture on the camera to f/2 or smaller taking a picture makes the body lock up with an error. I have to power down the camera to get it going again and the recorded frame is black. The camera also makes a weird, almost chirping sound when trying to take the picture.

Lens: 135/3.5 Same thing. f/4 is okay but f/4.5 and smaller cause an error.

Lens: 28/3.5 Same thing but at a somewhat higher f-stop.

I thought it might be a camera problem with slow shutter speeds but nothing similar happens when I attach an AF lens.

I tried my M42 lenses with a generic, non-electronic adapter and although I can't set any aperture value I tried various shutter speeds and no problem.

Anyone know what this is...


The error was reported by Arkku in :
http://www.dyxum.com/dforum/forum_posts.asp?TID=6242&PN=8
In my opinion,this error maybe caused by the len's thread. The thread of same lens are too fat,and blocked the apature driving arm.
I have done the experiment, confirmed, if use the adapter without the len. The error never appears.
Regarding different lens, The result is also different. Just as your reported. When use my takumar 50/1.4 , they work well. but use a AUTO REVUENON 50/1.8, this error will be observed.
So, I bend the apature driving arm outward a few . The error is solved.
Some of adapter's user successfully solved this problem as my way.
http://eadpt.com

M42 adapter with Focus Confirmation
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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: 10 April 2008 at 19:14
I can verify that the error indeed disappears if you do not have a lens attached. Personally I left the aperture driving arm alone and just shoot with the camera set to wide open.
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Bob J View Drop Down
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Post Options Post Options   Quote Bob J Quote  Post ReplyReply Direct Link To This Post Posted: 11 April 2008 at 12:46
A bit of advice here - I'm tempted, but I'm not sure how much benefit there would be...   

How much benefit is there in using one of these adapters for a fish-eye?

I find absolute focus with this Zenitar that I've borrowed quite difficult to judge (although DoF is pretty good in any case) - Might focus confirmation help? I'm also interested in having AS working, at very least so that I don't have to remember to turn it off...

Also is there any benefit for exposure on matrix metering if the camera knows it is dealing with a fish?

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Post Options Post Options   Quote Ozoger Quote  Post ReplyReply Direct Link To This Post Posted: 15 April 2008 at 22:46
Will this adapter work with my Sigma 600mm f8 MF mirror lens? I would love to have SSS with it. I noticed some other semi-circular adapters, can I modify my Sigma in some way?

Also I noticed 600mm was not listed as a compatible focal length... ?

Thanks, it sounds great!
A700/NEX-5/8mm Samyang/20-40 f2.8 sigma/50 f1.4/100 f2.8 macro RS/70-210 f4/600 f8 sigma/Slingshot100 flicker:ozoger
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Gabriel View Drop Down
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Post Options Post Options   Quote Gabriel Quote  Post ReplyReply Direct Link To This Post Posted: 15 April 2008 at 23:08
Originally posted by Bob J Bob J wrote:

How much benefit is there in using one of these adapters for a fish-eye?

I can't really tell you if it helps for focus, as most of my shots with the 17mm Takumar fish are at infinity and f/8.
What I can tell, however, is that it allows me to go down to 0.5s with reliably good results (slower speed sometimes come out fine, but it's not really what I'd call "reliable")
Pic a day 2008 /2009/2010 galleries
 



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Post Options Post Options   Quote KonicaA3 Quote  Post ReplyReply Direct Link To This Post Posted: 16 April 2008 at 01:20
Originally posted by Bob J Bob J wrote:

A bit of advice here - I'm tempted, but I'm not sure how much benefit there would be...   

How much benefit is there in using one of these adapters for a fish-eye?

I find absolute focus with this Zenitar that I've borrowed quite difficult to judge (although DoF is pretty good in any case) - Might focus confirmation help? I'm also interested in having AS working, at very least so that I don't have to remember to turn it off...

Also is there any benefit for exposure on matrix metering if the camera knows it is dealing with a fish?



Bob,
Don't know if it knows it is a fish, IMHO I doubt it, however, that said, it is invaluable with the a200, a300, a350 to allow using in Aperture mode as opposed to Manual only

Keith
Sony A77ii | Sigma APO 75-300 F4-5.6 | Minolta 70-210 F4 | Tamron 18-250 F3.5-6.3 Di |Minolta 35-70 F4 | Minolta 100-200 F4.5 | Sigma 18-125 F3.5-5.6

http://www.flickr.com/people/imagesbykeith/
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Post Options Post Options   Quote pepesaspa Quote  Post ReplyReply Direct Link To This Post Posted: 28 April 2008 at 21:14
Anyone know if it works stabilizer with a goal 1000mm f10 as the MTO 10/1000?
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Bob J View Drop Down
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Post Options Post Options   Quote Bob J Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2008 at 18:01
He says he can input 1000mm and the aperture would not be critical to AS/SSS (although focus confirmation would not work of course).

I ended up ordering one of these for a 16/f2.8, and it seems to work very well - you have to remember to keep the camera thinking it is exposing at the highest aperture (f2.8) in my case, but it works very well.

An interesting side-note - with a film camera (or with my 800si at least), the camera recognises that the lens is MF only - with my 5D the AF blade will spin if I've forgotten to switch to MF, but the film body knows better - I guess this must be the adapter telling the camera not to bother with AF... makes me wonder what a digital body does with the STF - does it try to set it to infinity on startup?
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Post Options Post Options   Quote Bob J Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 2008 at 13:00
A thought for anyone ordering one of these (and they are very good)...

You can get overexposure if the aperture on the camera is set to anything other than wide open (the actual lens diaphram can be set to whatever you like which is what really matters) - in a way it would be easier to avoid this if the adapter told the camera that the maximum and minimum aperture for the lens were the same - perhaps James might comment on whether this is possible/practical?
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Post Options Post Options   Quote JamesLaoT Quote  Post ReplyReply Direct Link To This Post Posted: 26 May 2008 at 05:03
Originally posted by Bob J Bob J wrote:

A thought for anyone ordering one of these (and they are very good)...

You can get overexposure if the aperture on the camera is set to anything other than wide open (the actual lens diaphram can be set to whatever you like which is what really matters) - in a way it would be easier to avoid this if the adapter told the camera that the maximum and minimum aperture for the lens were the same - perhaps James might comment on whether this is possible/practical?


There is a complex but the only right way to avoid overexposure and can record right aperture in Exif.
We can;
   1) Wide open M42 Len's aperture
   2) Set camera's aperture to what you want
   3) Focus and helf-press shuttle to check focus confirmation.
   4) Press AEL to lock exposure value
   5) Set M42 Len's aperture same as Step 2)
   6) Fire...

   In this way, What our did just as same as what the camera did when it use an AF len.
   Tips:
     1)Should Set camera in aperture priority (Mode A).
     2)From camera's menu, we can set AEL as press once for lock/unlock
:)
http://eadpt.com

M42 adapter with Focus Confirmation
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Post Options Post Options   Quote lionoche Quote  Post ReplyReply Direct Link To This Post Posted: 20 November 2008 at 14:31
Hi,

Considering to purchase one of these adpaters, I would like to know if the adapter makes the camera behaves like with SSM lens.
I am concerned about the AF motor of the body trying to drive the lens at start-up and making noise.

Clearly that is what I am talking about (taken from another M42 - Minolta AF adapter with focus confirm)

motor will starts and make a few seconds noise, to self-examine

Thanks in advance for your help
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 20 November 2008 at 14:39
I just tested on my A700 as well as KM5D with a JamesLaoT chipped adapter and clicking sounds is exactly the same as after switching on an AF lens focussed at infinity. There is no AF drive noise trying to get a (non-AF) lens back to infinity on either of the two cameras (Both cams were switched to MF)

Edited by pegelli - 20 November 2008 at 14:42
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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Post Options Post Options   Quote lionoche Quote  Post ReplyReply Direct Link To This Post Posted: 20 November 2008 at 16:30
Hi,
Thanks for your answer !
Do you think this is specific to the JamesLaoT adapter ?
Do you get AF confirm from the camera even if the switch is in MF position ?
Clearly, the reason why I am asking is that I heard about this issue being specifically adressed sometimes ago.
Can anyboy confirm ?

Edited by lionoche - 20 November 2008 at 16:31
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