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contax ax autofocus question
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PostPosted: Wed Dec 08, 2010 10:45 pm    Post subject: contax ax autofocus question Reply with quote
hi all

i am feeling politically incorrect, so i want a film camera on which i can autofocus my c/y mount lenses. the ax seems to be the only option.

my question is will it autofocus ALL c/y lenses or is there some limitation i should know about? i am mostly concerned about my yashica ml lenses and my planar T, but i also have a nice tokina atx zoom, and im planning on an 85mm planar....

thanks!


PostPosted: Wed Dec 08, 2010 11:28 pm    Post subject: Reply with quote
The AX's autofocus works with all Contax lenses except for:

- Mirotars (mirror lenses)
- lenses with minimum aperture f/5.6 or slower (basically, just the 100-300 zoom in the longer end)
- focal duplicators, extension tubes, bellows

I have no information about non-Contax lenses, but logic would say that the same rules as above would apply.

With lenses of focal lenght of 100mm or shorter, the lens will have to be manually focused to infinity prior to use with autofocus. This means that the lenses that use an internal floating element to optimize the performance at closeup distances will lose this advantage (because the focusing is done with the movement of the film plane instead of the floating element) and will perform like normal lenses i.e. you will have a (probably slight) decrease of performance at the close focusing distances compared to the best performance that the lens can give. The list of such lenses with floating elements is not short in the Contax catalogue:

- Distagon 15mm
- Distagon 16mm fisheye
- Distagon 18mm
- Distagon 21mm
- Distagon 28mm f/2
- Distagon 35mm f/1.4
- Planar 55mm
- Planar 85mm f/1.2
- Makro-Planar 100mm
- all the Contax zooms (Vario-Sonnar)

There are also the 2/200 and 2.8/300 lenses, but these will not have to be manually set to infinity (and in any case they are so expensive that almost nobody has them).

I have the AX since two years. It is a very nice camera but the bright large viewfinder really makes the autofocus redundant.
The real benefit of the autofocusing system of the AX is that with it, all Contax lenses become macro lenses - and with no loss of luminosity like with tubes or bellows extensions.

_


PostPosted: Thu Dec 09, 2010 12:21 am    Post subject: Reply with quote
wow! thank you orio for the amazingly thorough reply, that is such great information! may i ask what you mean that all contax lenses are made macro by virtue of the autofocus nature of the camera?


PostPosted: Thu Dec 09, 2010 6:30 am    Post subject: Reply with quote
I also read that this camera, which looks amazing : ) also takes M42 lenses with an adapter, so some old Zeisses should work AF as well.


PostPosted: Thu Dec 09, 2010 11:48 am    Post subject: Reply with quote
I was wondering several times, it'd be really nice to have a digital body with this AF mechanism. Smile


PostPosted: Thu Dec 09, 2010 11:56 am    Post subject: Reply with quote
rbelyell wrote:
wow! thank you orio for the amazingly thorough reply, that is such great information! may i ask what you mean that all contax lenses are made macro by virtue of the autofocus nature of the camera?


The camera can move the film plane towards the lens for focusing. This reduces the so call "register distance" the nearer you move the film plane towards the exit pupil of the lens. It is possible to use this mechanism to obtain a minimum focusing distance that is smaller than what the lens would achieve if the film plane stayed at the regular distance.
So by way of this feature, you can turn all Contax lenses into macro lenses. Isn't that cool?


PostPosted: Thu Dec 09, 2010 2:36 pm    Post subject: Reply with quote
As Orio says,

In normal case (film plane is toward the lens):


In Macro mode (film plane is toward the back):


The entire mirror box with penta prism and film transport moves for AF.
The camera has "macro" mode (into to the second photo, 10mm back),
which equates to that you have the 10mm tube built-in the camera.


PostPosted: Fri Dec 10, 2010 1:29 am    Post subject: Reply with quote
orio, not only is that cool, its amazing! why dont we all own this camera?
especially if hexi is correct and my m42>c/y adapter will also yield same result? this is a really amazing piece of technology....i cant wait to find a well priced model!


PostPosted: Sun Dec 12, 2010 2:29 pm    Post subject: Reply with quote
Quote:
The camera can move the film plane towards the lens for focusing. This reduces the so call "register distance" the nearer you move the film plane towards the exit pupil of the lens. It is possible to use this mechanism to obtain a minimum focusing distance that is smaller than what the lens would achieve if the film plane stayed at the regular distance.
So by way of this feature, you can turn all Contax lenses into macro lenses. Isn't that cool?


Moving the backplane doesn't change the register distance of the lens. Furthermore, moving the backplane forward will move the focus towards infinity - and past the infinity if the distance between the lens and the backplane can be made shorter than the register distance of the lens - hardly a useful option. OTOH, moving the backplane away from the lens is equivalent to adding a short, adjustable macro ring, which will with short lenses facilitate macro photography, at least in combination with in-lens focusing. With long lenses the backplane focusing range is more limited.

Veijo


PostPosted: Sun Dec 12, 2010 2:37 pm    Post subject: Reply with quote
And with some lenses the movement of the back plane might not be enough, so pre-focusing at the lens is necessary.


PostPosted: Sun Dec 12, 2010 3:18 pm    Post subject: Reply with quote
vilva wrote:
Furthermore, moving the backplane forward will move the focus towards infinity


yes, I wrote it the opposite by mistake.


PostPosted: Sat Dec 18, 2010 1:51 pm    Post subject: Reply with quote
there is one other option to use C/Y lenses with autofocus, but this may be even more political incorrect. You can use a Yashica AF camera with the special 1.6x teleconverter, which was invented just for this purpose.
It will change the focal length and you loose about 1,5 stop, if I remember right. But it brings autofocus into your good old C/Y glass.

Gerd


PostPosted: Sat Dec 18, 2010 9:59 pm    Post subject: Reply with quote
thanks everyone! just bought an ax on ebay--supposedly mint for $420usd, i think a very good price if description and pictures were accurate. cant wait to try out....


PostPosted: Sun Dec 19, 2010 1:25 pm    Post subject: Reply with quote
congratulations to your new axe!

Gerd Very Happy


PostPosted: Thu Jan 06, 2011 1:34 pm    Post subject: Reply with quote
as a post script, i received the ax. first off it is quite possibly the biggest slr ever made! i cannot imagine, nor have i ever seen a larger camera.

having said that, wow! what an amazingly engineered instrument! now virtually all my contax and m42 lenses are autofocus! this thing is just insanely well put together and well thought out. its like the uber slr!

and even though its huge it somehow feels just great in your hands and its soooo much fun to use! i have not gotten back my first roll yet, but i sure had a great time taking pictures with this beast.

thank you again to all who helped me with this decision.
tony


PostPosted: Wed Jan 26, 2011 8:01 pm    Post subject: Reply with quote
rbelyell wrote:
as a post script, i received the ax. first off it is quite possibly the biggest slr ever made! i cannot imagine, nor have i ever seen a larger camera.

having said that, wow! what an amazingly engineered instrument! now virtually all my contax and m42 lenses are autofocus! this thing is just insanely well put together and well thought out. its like the uber slr!

and even though its huge it somehow feels just great in your hands and its soooo much fun to use! i have not gotten back my first roll yet, but i sure had a great time taking pictures with this beast.

thank you again to all who helped me with this decision.
tony



Can you please post some samples and share your experience so far?

I'm thinking of getting one very soon


PostPosted: Wed Jan 26, 2011 9:22 pm    Post subject: Reply with quote
hey hari

tbh, im sorry to say ive kinda given up posting samples on this site because, for some reason i have yet to ascertain, they always come out looking like garbage--washed out. low contrast, just awful and never close to how i see them on my screen. i am sure the fault is mine, but ive tried a lot and always the same result.

i have only shot one roll on the ax, and much of it was color indoors without flash. they came out surprisingly good, but all the photos were about a half stop or so dark. it could be my metering, it could be i need to use the spot metering function more, or really that i just need a some more experimenting time than 1 roll!

my initial imoressions are very very positive. althiugh it is huge, it somehiw feels very comfortable in my hands. the AF function works perfectly with MF lenses, not only contax, but any lens that you can get on an m42 adapter also works perfectly. all my pics were nicely focused, even in low light. i have one portrait that i took outside that was stunning, but like i said close to a stop too dark.

the engineering on this cam is just outstanding. it just does everything! i really love it. i actually have a function to attend this weekend that i may take it to. in any event i HIGHLY recommend it to you. i have seen your work, and know your lens collection, and i think yiu would both have a ball with it and use it to much better result than i!


PostPosted: Fri Jan 28, 2011 7:24 pm    Post subject: Reply with quote
rbelyell wrote:
hey hari

tbh, im sorry to say ive kinda given up posting samples on this site because, for some reason i have yet to ascertain, they always come out looking like garbage--washed out. low contrast, just awful and never close to how i see them on my screen. i am sure the fault is mine, but ive tried a lot and always the same result.

i have only shot one roll on the ax, and much of it was color indoors without flash. they came out surprisingly good, but all the photos were about a half stop or so dark. it could be my metering, it could be i need to use the spot metering function more, or really that i just need a some more experimenting time than 1 roll!

my initial imoressions are very very positive. althiugh it is huge, it somehiw feels very comfortable in my hands. the AF function works perfectly with MF lenses, not only contax, but any lens that you can get on an m42 adapter also works perfectly. all my pics were nicely focused, even in low light. i have one portrait that i took outside that was stunning, but like i said close to a stop too dark.

the engineering on this cam is just outstanding. it just does everything! i really love it. i actually have a function to attend this weekend that i may take it to. in any event i HIGHLY recommend it to you. i have seen your work, and know your lens collection, and i think yiu would both have a ball with it and use it to much better result than i!


OK, i'm sold! ordering it! Very Happy

Ever since Orio mentioned shooting in film in a different conversation, its been on the back of my mind to get my film camera out but I sold almost all the R-lenses and I'm not in the mood to shoot with the ones I have :/

Since I have some C/Y lenses and this camera always intrigued me and there's a decent one for sale around and somehow you wrote a post about this very camera and you seem happy with it and i'm not drooling at any other equipment at the moment and I returned the 5D - waiting for a good deal on a 1Ds MK2 or 1Ds MK3, I need a FF body for my C/Y lenses and everything ties in to the T, I will get this beast of a camera to teach me a few things

Pity you cant upload your images to your satisfaction ... i'd absolutely love to see some of your work!

If it's not a hassle, could you please mail me a few of your AX shots to dementedjesus@gmail.com? Preferably without pp

Thank you for your kind compliment, i'm finally getting the hang of taking some decent images Smile


PostPosted: Sun Jan 30, 2011 8:47 pm    Post subject: Reply with quote
OK! Won the auction!

Click here to see on Ebay.de

Condition seems to be excellent! I can't wait till the beast gets delivered to me!

My hands are pretty big and this beast should fit well.

I'm also curious to see how quickly the AF works - I've read a million conversations on this and as usual, I'd like to be my own judge

Anybody else have any pix taken with this cam? Flickr spews out some random stuff that doesn't impress me and i'd like to see some skilled hands that put this camera to good use!


PostPosted: Mon Jan 31, 2011 1:54 pm    Post subject: Reply with quote
congrats man, you will love this thing! it really is an amazing piece of engineering to be able to ake lenses made as manual focus an. magically turn them into autofocus! the af will work faster than yiu anticipate. the reason i havent sent you any pix is because i really only shot one roll, mostly indoors in very low light, pushing film two stops, so i really didnt think that would present a fair view of the camera. i would be curious though if you notice the camera shoots a little dark--for me like a half stop or so, but again, i was pushing film and it was only one roll...


PostPosted: Wed Feb 02, 2011 9:49 pm    Post subject: Reply with quote
rbelyell wrote:
congrats man, you will love this thing! it really is an amazing piece of engineering to be able to ake lenses made as manual focus an. magically turn them into autofocus! the af will work faster than yiu anticipate. the reason i havent sent you any pix is because i really only shot one roll, mostly indoors in very low light, pushing film two stops, so i really didnt think that would present a fair view of the camera. i would be curious though if you notice the camera shoots a little dark--for me like a half stop or so, but again, i was pushing film and it was only one roll...


Got the beast today. Was worth the money spent - it's really MINT! Not a single scratch or even hair line paint loss anywhere on the body.

True to what you said, the camera is pretty big but fits nicely in my hand.

I already have a few rolls of Ektar 100 and various color/B&W rolls of Ilford. Now i'm waiting for the batteries+charger.

I will take a weekend trip to Berlin to start the film fun!

I have to say this is like going back a long way in evolution after getting used to the size and weight of the M9 + lenses



PostPosted: Wed Feb 02, 2011 10:00 pm    Post subject: Reply with quote
really happy for yu man! looks like a beauty! wait til you see how this thing autofocuses built to be mf lenses, you will just love the engineering involved.

i would definately shoot a couple rolls of color slide film with your planars. i will be curious to your results, as i mentioned, my onky roll came out mostly 1/2-1 stop too dark abd curious if its a camera thing or a me thing (or maybe my cameras meter thing!). im waiting for the weather to get a little better and im going to put a roll of provia in and go to town!

good luck and let me know how it turns out!


PostPosted: Wed Feb 02, 2011 10:45 pm    Post subject: Reply with quote
Congrats! I look forward your shoots !


PostPosted: Tue Feb 08, 2011 11:20 am    Post subject: Reply with quote
I finally got some time yesterday to take the AX + 50/1.4 MM out to the mall.

Will give the rolls for developing this evening!

I'm excited!

Question - I bought this viewfinder -> Click here to see on Ebay.de that doesn't want to work with the AX.

Am I missing some adapter/connector kinda thing? The AX has a screw-in mechanism and my other 3rd party VF won't work on it so I went looking for a Contax VF :/


PostPosted: Tue Feb 08, 2011 11:43 am    Post subject: Reply with quote
After looking at some pictures of the VF online, it might be that the square VF adapter is stuck on the VF - it might be possible to unscrew it so I can use built-in ring and screw it on the AX body

Will update with Go/No-go when I'm back in the city

Inputs welcome!
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