CI Photocommunity

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.

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.



New Member

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


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?


Active Member
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.


New Member

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.


Thanks Brian, I already found this info.

It looks pretty nice on paper. What looks even nicer is this lens`s price on
Please, Log in or Register to view URLs content!
- $849. I just was curious about the real difference in image quality - but if there is no noticeable difference at all I`ll definitely go with this lens and with Arsat 30 for fish-eye. I just don’t see how 10mm difference in focal range may cost $580 (considering that resulting image quality will be the same).
2 additional steps behind from the subject matter does not cost that much, at least it is so for me…


Wojo, you`re just reading my mind!

I was thinking about the same thing. 2CR5 has 1.3 AH - so anything above this will be OK.

I`m thinking about something like this:
Please, Log in or Register to view URLs content!

I was thinking about this item - 840110 - 6 volt, 3.2 AH SLA, just becouse of its slim body shape.

I looked at the wires in the COntax 645 battery grid - it definetely cannot consume more than 100mA-200mA from battery - wires are very thin, just like regular computer wires you put over the circuit.


Has anyone used rechargeable batteries from this company (
Please, Log in or Register to view URLs content!

How long can a charge last when used with the C645?

Any input will be appreciated.


> I recon there is very little difference in Image quality between the 45 mm and 55 mm CZ Distagon's (I have only the 45 mm, of the two).

The price difference would be due to the fact, that the 45 mm is made with 9 lenses and it is a F 2,8 lens, making it bigger with larger glass surfaces to polish, assemble and adjust, and hence more costly to produce. Also correcting a 45 mm wideangle lens of this speed to the standars CZ would require, might call for more exotic - and thus more expensive glass types.

The 55 mm is made with 7 lenses, and it is "only" a F 3,5 lens - thus smaller, and with smaller glass surfaces. And probably easier to correct for the designer, very likely not calling for the most exotic glass types.

Yes, you can walk two steps back - but that will not give you that extra F stop in terms of speed, you will not have the same perspective, nor be able to obtain the same depth of field with 55 mm.

So when choosing between the two lenses you have to define how much these considerations matter to you, and whether it is worth the extra money for the 45 mm.

On thing is for sure - you can make absolutly outstanding images with both lenses.

Happy shooting!





site says: A fully charged battery will not last as long in the camera as a lithium but, with normal use, you should get a minimum of 10-15 rolls of film out of it before recharging.

I would not expect any miracles... Not to mention that SLA battery setup will be probably much cheaper.