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55 vs 45 mm lens



I`m trying to decide what wide angle Zeiss glass to choose for my Contax 645, actually, I want to understand what is the price/quality ratio value for the 55 and 45mm distagons .

I tried to find MTF charts for 55mm Distagon but it appears that kyocera site doesn`t give `em for some reason not to mention that it shows 30mm lens data for 55mm lens (what a crying shame! It is almost most expensive glass money can buy and they don`t even bother to have a working web site...

Did anybody have a chance to compare 45 vs 55mm lenses? How do they perform wide open and at aperture 8?

55mm one is almost 2 times cheaper than 45mm one - right now I see 55mm distagon on ebay for sale for about of $700. Does this speak for itself?
Is 55mm lens 2 times worse than 45mm by its
distortion, resolution?

Does this info exist anywhere in the net?
Hi Paul,

I have used but don't own the 55mm but I do have the 45mm...and the 35mm. I don't really care about MTF charts, I care about how the image looks and feels. The 45mm is fantastic and it is my most used lens in my bag. I do mostly landscape work with it and I think a 45mm does a much better job as a wide angle than the 55mm. You won't be dissappointed with it if your looking to use it for scenics.


I, like Guy, haven't studied the MTF charts. I have both the 45 and 55 lenses. I have not noticed one lenses performance being better than the other. Both (for that matter ALL the lenses in the system) are without peer.

Brian J Nelson

why searching around at Kyocera websites? Just click on this site in the navigation bar on "Manuals"

There you will find a section for The N-mount and 645 lenses with all MTF data available.
I have one more question to ask - have anybody tried to use an AC adaptor with Contax 645 in a studio? I have a couple of 6v 200mA units (just like for CD players and stuff like that) but I`m not sure if this camera can accept a current from impulse AC-DC unit.
Has anybody tried it?
Paul you can use a mains unit at 6 Volt but you need 2.5 or 3 Amp not 200Ma. You may get away with 2 Amp but if it is getting heavy use you will burn out the power supply.
The camera will work on 5 Volts so look at a power supply from a computer 5 Volts output.
I have also used 6 Volt 10 Amp lead acid battery smaller versions are available like 4 and 6 Amp.
All model shops sell these at reasonable prices
Thanks Bob.

It`s a good idea about taking it from computer - I`ll give it a try.
A little extra info, about the batteries.
I use a 6v 6.5 hr gel cell also known as a sealed lead acid battery.
The can be had at Home Depot for around $12 IIRC.
They're sold as replacement batteries for emergency lights and work like a charm.

I found the little instruction book that came with the 55 lens-(I didn't find one for the 45 though) If you wish, I can e-mail you an image of the MTF curves that are published in the book.