Contax 220 vacuum insert

[david_chilvers]

I hastily shot a couple of rolls of 220 100f film yesterday with the

Contax vacuum insert and the first indications are that it does make

all the difference. The images were good with the standard 120 insert

but lacked the quality that i had expected from the contax lenses.

I`m quite amazed how much better the vacuum insert is when one

considers the maker which brings me to the conclusion that my

previous experience with 645 reverse curl backs that I have owned

have lacked that final bite for the same reason maybe. I have a high

amount of static electricity about me in dry weather and must wonder

if in some strange way the centre of the film is attracted away from

the pressure plate( silly i suppose) but it makes you wonder.

Now! I can`t wait to use the vacuum back with tripod and mirror up

where as before it didn`t seem to make a lot of difference.The

difference between images taken with an RF645 and fuji 6x7 rangefinder

(which have always been good) vs 645 slr`s and the different film

path seems to be answered here.

I started to question my photographic skills of late and referred

back to my digital images taken with a Canon D30 and it could make

sense now. The digital images(although much lower res)were always

sharper across the whole frame and of course the chip is completely

flat and not subject to the same stress and strain as film.

BTW at the pro lab where my films were processed today the guy was

explaining to me about their use of special vacuum backs that they

use in the studio with 10x8 cameras, more so when they shoot

downwards and the film is more liable to sag in the middle.

 

Anyway, I just thought I`d share my findings with the group.

 

Dave c

[a m]

David,

This is very interesting. Please share the results when you conduct the more controlled experiment with tripod and mirror up. Readers with long memories may recall that the Linhof Aero Technica had a vacuum back for 70 mm film and possibly for 220 film. A number of 4x5" cameras also have been equipped with vacuum, including an ultra-precise system from Lichtenstein used for architecture and photogrammetry. All 9x9" cameras for aerial photography have vacuum platters. However, size does matter. The Contax RTSIII has a vacuum back, but no comparison tests that I have seen demonstrated that it made any obvious improvement with 35 mm film. Neat idea, though, and clever engineering.

[Robin Smith]

David

 

I have to say I am quite surprised you can notice any difference, particularly when you say that with the 120 film the shots were actually not the"..quality that i had expected from the contax lenses". I find this almost unbelievable - where you really taking pictures at equivalent shutter speeds and apertures with tripods and so on? I am not saying that it might make a small difference, but a difference such that it makes you wonder whether the equipment performs well without it astonishes me - how could Contax put out such a bad 120 back in this case?

[danny burk www.dannyburk.]

I wonder whether there might be another issue involved with David's setup. Previously interested in the image quality difference between vacuum and non-vacuum backs, I questioned at least 4-5 other Contax 645 vacuum back owners to inquire whether they noticed a difference when using the vacuum back. Every person said "no", so I have not purchased one. The images that I obtain from my camera, with normal back, are stunningly sharp and very worthy of Contax lenses IMO. I have two backs, one usually with 220 transparency and the other with 120 b&w neg - both give equally good results.

 

Any other vacuum back owners here? What differences have you noticed, if any?

 

Danny www.dannyburk.com

[sal_santamaura]

How? Simply by matching film flatness standards of all other reverse-curl 120 backs on the market!

[david_chilvers]

Again

 

I share all of your concerns/misbeliefs and was pleasantly surprised by these initial results.

Consider the facts! I am a photographer of some 30 years and have done the rounds as a federation judge, I don`t have money to throw away (£299)and wouldn`t put myself in a position (like I was in today)trying to obtain 220 type of my favourite stock film for no reason.Plus, would Contax introduce an item that they really felt wasn`t needed? and add a gizmo to an otherwise terrific sensible camera that has just about the right amount of technology?

 

No I didn`t take note of camera settings at the time but have looked at the print out in the film margins) but the weather and conditions were similar but i did shoot samples wide open f2 on the planar, f8 and f16 and similar on the 45 mm lens keeping the shutter speed up where I could as usual with both inserts. I am now going to do some more controlled shots with tripod and MU. I share concerns about handholding but thats the way I like to walk about and take pictures so any camera I have has to fall in line as far as that goes ( is that too much to ask)and if a Bronica rf645, fuji6x7, Fuji6x9 and Mamiya RZ can produce good results then i don`t think it`s too much to ask that a superbly made bit of kit with a well damped mirror(BTW I use mirror up sometimes when hand holding cos it`s so easy with the Contax)can do the same, but obviously do use a tripod when needed. I`m not an expert but I do know a good slide when I see one and the vacuum back seems to work for me. We shall see with the next batch but please don`t shoot me down for wanting to share my findings.

 

Regards(further comments are very welcome)

 

Dave C

[Robin Smith]

"would Contax introduce an item that they really felt wasn`t needed?"

 

I think they put it in the vacuum back in the RTSIII for no real benefit. They felt that it looked smart and was highly marketable - as it happened I don't think it has worked in attracting people to buy the camera. Sometimes the fact that something is available does not mean it is worth it (or even better) - curved field projection lenses are another case in point.

 

David - I am still sceptical that there is any real difference, but I am naturally interested in what you come up with. I am happy to be proved wrong.

[triblett_lungre_thurd]

well judge dave,

 

good fer you and yer new bit of kit. the dektol atom splitters and me(i speak fer the sharpness freaks only) would prefer rigorous bench testing at high mags... but if you say so.

 

me

 

p.s. i never could find a fan in the RTS3 i held either? hokum...

[william_yu]

Hi,

 

After these months, has anybody done more testing on the vacuum back to see whether it does make a difference or not? If it does I want to buy one for my Contax.

 

Thanks,

[michael_dimarzio]

I am hoping that somebody will add some new data to this thread, would the vacumn back be more critical for macro shots? Any macro guys out there using it?

[roger_michaelson]

Zeiss has posted this for you to know.

 

http://www.zeiss.de/C12567A8003B58B9/allBySubject/134AEE504E89CD50C12569620039712C

 

In brief, if you are going to stop shooting for about more than 10 mins while, in my case, the model changes, the make up changes etc etc etc and you have not shot the whole roll, then the vacuum should keep your film sparkly flat. If you let the film rest a long time and you dont have the vacuum then you can expect to have non flat surfaces towards the edges and certainly like stated in the post, in the center if left there beyond 2 hours.

 

I have also found that fro macro shots when the system has to be "aimed" downwards the film (120 mainly because of the psper companion) will tend to fold downwards real quick. But this is a very special case.

 

Enjoy your systems.