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Techart adapter and Contax G question

scho

Well-known member
Just trying my CG 35 planar mounted on the A7r-FS in B&W mode with no filter in low light. AF was a struggle in dim pharmacy lighting, but MF with magnification worked very well. Shot at f/2.8 with focus on eyes of the model in the poster.

 

Cindy Flood

Super Moderator
I have G 35 (m- mount), 45 and 90 and Carl is correct. They are so easy to manual focus. I love the manual focus on the Techart, it really is smooth.
 

Jim DE

New member
Yeah I have never had a issue manual focusing these lenses with my Kipon.... I had a stroke awhile back and have limited usage of my left hand and think the finger wheel could be a issue for me to manual focus compared to a full ring focus on the Kipon. My hand is odd in what it can and can't do. Like I can turn a door knobbin one direction but not the other or I can't unlock a key lock but can lock it with the key .... On the Kipon I have my hand in one position to turn the focus clockwise and reverse it to go counter clockwise... I have to do the same when zooming lenses as well.
 
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lamlux

New member
Happy to report i've received an "used" TA-GA3 from eBay and successfully updated the firmware to the latest 2.2.0 (I noticed 2.1.0 crashed the app, must've deleted it from their server)

With my G 45/2 it works wonderfully, I actually took this lens apart to clean it and overhaul it, learned a thing or two through trial and error.. tested it with a mint 9mil. serial 45/2 and it worked beautifully. I have got my G 45/2 to work the same way now and it is FANTASTIC. It is what I wanted in V1 of the adapter a year ago. Albeit aided with phase detection its rapid in good light, and ok in low-light though that can use improvement.

I'm now looking for examples of the 21 and 28 Biogon photos from the A7RII if anyone has any, strongly considering picking one up just because of the value there.. and i'm using a G1/G2 film setup too. Also ordered a G 90/2.8 for $150 yesterday i'm pretty ecstatic at the usability here.

Given some time i'll be writing up a summary of important things I think newcomers will find useful; i.e. firmware upgrade procedure, focus tuning, and other tidbits I found out the hard way..
 

Annna T

Active member
Happy to report i've received an "used" TA-GA3 from eBay and successfully updated the firmware to the latest 2.2.0 (I noticed 2.1.0 crashed the app, must've deleted it from their server)

With my G 45/2 it works wonderfully, I actually took this lens apart to clean it and overhaul it, learned a thing or two through trial and error.. tested it with a mint 9mil. serial 45/2 and it worked beautifully. I have got my G 45/2 to work the same way now and it is FANTASTIC. It is what I wanted in V1 of the adapter a year ago. Albeit aided with phase detection its rapid in good light, and ok in low-light though that can use improvement.

I'm now looking for examples of the 21 and 28 Biogon photos from the A7RII if anyone has any, strongly considering picking one up just because of the value there.. and i'm using a G1/G2 film setup too. Also ordered a G 90/2.8 for $150 yesterday i'm pretty ecstatic at the usability here.

Given some time i'll be writing up a summary of important things I think newcomers will find useful; i.e. firmware upgrade procedure, focus tuning, and other tidbits I found out the hard way..
Concerning the lenses : they were designed for film as you know and the wide angle design (Biogon) doesn't cope well with the short flange distance of the E mount, nor with the high resolution of the sensors : the problems come from the angle of light striking the sensor too steeply. This results in smeared corners and depending on the model, magenta cast. On the A7r the 28mm was a very bad performer. I didn't even test with the A7r2. In order to mount the 21mm you need to cut the black plastic wings protecting the rear elements. The lens is fabulous with film, but produces smeared corners on digital bodies from what I have seen, so I didn't even care to cut those rear wings.

Leica M wide angles get the same kind of problems. Some send their sensors to Kolari in rider to have it modified. Some lenses then produce better results, but it isn't perfect. I think that modification isn't very efficient for Contax G lenses, but I don't remember where I read that.

The two best performers are the 45mm and 90mm. With the 35mm coming third.

Thanks for your report on the new firmware BTW.
 

Jim DE

New member
I have the 21mm but refuse to cut it to fit inside a E mount without hitting the sensor. Mainly because I have never seen what I would call a good image with a 2 CG on a digital and it is a stellar piece of glass on the Contax g2 with color positive film.

I started to try and mount the 28 on my a7r2 but with ibis moving the sensor I really eliminated that idea to due to just how deep the 28mm fits inside the sensor box. Just too close for this old guy to feel comfortable especially when others say they have smearing and color shift as it has had open on every E mount since the original Nex5.

I also don't like the look of the 35 and replaced the 45 with the Sony 55 mm which IMO is stellar. The only lens I still have in my kit and will probably be the next replaced is the cg90mm.
 

yashima

New member
Happy to report i've received an "used" TA-GA3 from eBay and successfully updated the firmware to the latest 2.2.0 (I noticed 2.1.0 crashed the app, must've deleted it from their server)

With my G 45/2 it works wonderfully, I actually took this lens apart to clean it and overhaul it, learned a thing or two through trial and error.. tested it with a mint 9mil. serial 45/2 and it worked beautifully. I have got my G 45/2 to work the same way now and it is FANTASTIC. It is what I wanted in V1 of the adapter a year ago. Albeit aided with phase detection its rapid in good light, and ok in low-light though that can use improvement.

I'm now looking for examples of the 21 and 28 Biogon photos from the A7RII if anyone has any, strongly considering picking one up just because of the value there.. and i'm using a G1/G2 film setup too. Also ordered a G 90/2.8 for $150 yesterday i'm pretty ecstatic at the usability here.

Given some time i'll be writing up a summary of important things I think newcomers will find useful; i.e. firmware upgrade procedure, focus tuning, and other tidbits I found out the hard way..
Hi Lamlux,

You might be my saviour! Recently I just discovered my 45/2 developed some fungus inside the front element. However I'm completely perplexed to how to take this lens apart. I have taken many lenses apart before (and destroyed a few in the mean time), however I just dont know where to start with this one.

Do you mind giving me some pointers? Or if possible, some guidance photo. I would be very grateful.

Many thanks
 

jhe1971

New member
Hopefully I'm not beating a dead horse here. I just would like to know how slow/fast/accurate is autofocus with the Techart Contax G adapter/A7S combination. The Contax G lens I'm mainly interested in is the 90/2.8.

I have an Oly 100/2.0 already, but it would be nice to have an autofocus tele lens also. Of course there are native options available: Sony 90/2.8 macro (wich is stellar but quite bulky) and Zeiss 85/1.8 (smaller but more expensive and hard to find). Contax G 90/2.8 is compact and would be much cheaper even with the adapter.

So, if anyone has experience of the combination mentioned above, could you please share your experience?

Thanks in advance!

Best regards, Jyrki
 

lamlux

New member
Hi Lamlux,

You might be my saviour! Recently I just discovered my 45/2 developed some fungus inside the front element. However I'm completely perplexed to how to take this lens apart. I have taken many lenses apart before (and destroyed a few in the mean time), however I just dont know where to start with this one.

Do you mind giving me some pointers? Or if possible, some guidance photo. I would be very grateful.

Many thanks
Not sure how off-topic I can pull this here but i'll mention it for sake of the future searches..
Front name ring is easily unscrewed by using cork stop or similar (sink stop I use!), unscrew 4 screws securing aperture ring assembly and carefully remove the aperture indicator ring, and the aperture ring itself. Then you can remove the 4 screws that hold the element group (and aperture), basically the ENTIRE lens aside from the helicoil/mount.

From there you can figure out what to do :) Unscrew the rear element to clean that, or if you're handy, you can get into the fronts.

About 90/2.8 on the adapter, i'll be sure to chime in once my 90/2.8 arrives, though many here already use it and will probably chime in before.
 

Annna T

Active member
Hopefully I'm not beating a dead horse here. I just would like to know how slow/fast/accurate is autofocus with the Techart Contax G adapter/A7S combination. The Contax G lens I'm mainly interested in is the 90/2.8.

I have an Oly 100/2.0 already, but it would be nice to have an autofocus tele lens also. Of course there are native options available: Sony 90/2.8 macro (wich is stellar but quite bulky) and Zeiss 85/1.8 (smaller but more expensive and hard to find). Contax G 90/2.8 is compact and would be much cheaper even with the adapter.

So, if anyone has experience of the combination mentioned above, could you please share your experience?

Thanks in advance!

Best regards, Jyrki
The A7s and A7sII have the same AF as the A7r : they use only contrast detect (unlike the A7II and A7rII which are hybrid and use both contrast detect and on sensor phase detect). This means that the A7s and A7r can focus with the Techart adapters, but they are slow. That is OK for landscapes and immobile subjects, but not for moving subject unless you can prefocus. At least that is my experience with the A7r. I don't have an A7s, but I don't think it will be better in normal daylight, given that they share the same AF system. With the A7s you may have some advantage in low light maybe.

The A7rII is much faster to focus, but not as fast as a Canon lens with the Metabones adapter, which in turn is slightly slower than native lenses.
 
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Slingers

Active member
I have the version II of this adapter, the 90mm lens, and an A7S. As Anna says the adapter is slow and it does work. Image wise there are no problems but the adapter can have issues as seen in this thread. I have seen reports though, I think it was from a user here, that the firmware before the PDAF updates had improved all the problems on the CDAF cameras but I haven't tried to contact the manufacturer to see if I can get my older adapter updated.

Hopefully I'm not beating a dead horse here. I just would like to know how slow/fast/accurate is autofocus with the Techart Contax G adapter/A7S combination. The Contax G lens I'm mainly interested in is the 90/2.8.

I have an Oly 100/2.0 already, but it would be nice to have an autofocus tele lens also. Of course there are native options available: Sony 90/2.8 macro (wich is stellar but quite bulky) and Zeiss 85/1.8 (smaller but more expensive and hard to find). Contax G 90/2.8 is compact and would be much cheaper even with the adapter.

So, if anyone has experience of the combination mentioned above, could you please share your experience?

Thanks in advance!

Best regards, Jyrki
 

yashima

New member
@Lamlux: Thank you, I will give it another try today and if there's any problem I will PM to keep the thread clean.

@Slingers: Hi, a forum member said you successfully use a G35-70 with Techart AF adapter. Could I pls ask which version of the adapter it is? And how do you feel about its performance?
 

Slingers

Active member
I have used the zoom with both the version I and II of this adapter as the first version adapter I had so many problems with it I had to send it back. The zoom worked great for me on both adapters but in the exif it reports its the G21. Actually the G21 and G35-70 never have had any problems for me with the adapters only the G45, G90, and occasional problems when using the G28. I see though a lot of reports of the zoom not working so maybe I am lucky with mine but it is a black coloured version and maybe it's different. I find the zoom lacks a little contrast but is nice small package with decent sharpness for these cameras.

@Lamlux: Thank you, I will give it another try today and if there's any problem I will PM to keep the thread clean.

@Slingers: Hi, a forum member said you successfully use a G35-70 with Techart AF adapter. Could I pls ask which version of the adapter it is? And how do you feel about its performance?
 

yashima

New member
I have used the zoom with both the version I and II of this adapter as the first version adapter I had so many problems with it I had to send it back. The zoom worked great for me on both adapters but in the exif it reports its the G21. Actually the G21 and G35-70 never have had any problems for me with the adapters only the G45, G90, and occasional problems when using the G28. I see though a lot of reports of the zoom not working so maybe I am lucky with mine but it is a black coloured version and maybe it's different. I find the zoom lacks a little contrast but is nice small package with decent sharpness for these cameras.
Thank you. By working, do you mean autofocus works well also? Is there any magenta cast in the corner at all?
 

Slingers

Active member
These are with another adapter but an example on the A7S. They are not the best images but give an idea of the performance.

I believe 35mm f/3.5 not 100%

70mm f/8

50mm f/8

35mm f/8
 

yashima

New member
Thank you for the images. Do you have images from G45 at similar settings (ISO, f stop) with the A7s that we can fairly compare?
 

Jim DE

New member
I think I read on a Techart ad that the 3 works on everything but the zoom.

The zoom and 16 are the only two CG lenses I don't have in that series. Personally on digital for my tastes the 45 and 90 were the only two I used the others stay with the ContaxG2 which I still occasionally use when bored with digital.
 

Annna T

Active member
Well, I finally found the courage to put the 16mm on the TechArt adapter v. 2 (TGA-1B). I put the body into silent mode and took a few shots. But I have to get a new fully manual adapter for it. I wasn't able to get the magnifier and focusing was very difficult. I used zone focusing, but the bottom of the picture was sharp even in the corners, to my big surprise. However about half height, things turned very bad. I wasn't able to focus to infinity. I think that the problem is due to the screw on the adapter, which can't enter in the usual place (the 16mm is only manual and has a focusing ring). May be that I'll get a dumb adapter and try again to see how the lens will behave.

This is a perilous exercise : after the first tries I deactivated the silent shooting mode, but didn't remember it when I decided to give it another try.. So the shutter went against the rearelement and I got a camera error. Took me a while to realize. But once I replaced the lens with a native one, everything returned to normal. So no harm.. but still this is a perilous exercise and prone to cause damage to the shutter. The results aren't even worth showing. Next step : getting a dumb adapter.

Concerning the new firmware available : 2.2, I made the update yesterday, but still no luck with the 90mm. The adapter is however working fine with the 45mm.
 
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