CZJ pentagon six lenses on a Canon 5d MKII

[propellor]

Hi everyone,

My name is bart from Amsterdam, The Netherlands. I am thinking of using Zeiss Pentacon Six "Zebra's" on my Canon 5d MKII.

I am unclear about the following: I have read that the focal lenght of the Zebra's should be halved when used on a full size sensor. Others wrote that this is not true and that a 50mm Zebra acts like a 50mm on the 5D.

Can someone please enlighten me?

If a 50 acts like a 50, I would need wider lenses to make up my range. Would the M42 Zebra's be an option to get the same "feel and character" as with the P6 lenses and which ones would fit on the 5D?

The camera will only be used for filming in HD.

Thanks in advance.
Bart.

[sichko]

The focal length of a lens is defined even in the absence of a camera. So a 50 mm P6 lens does not change its focal length if you use an adapter to use it with a Canon.

[no-X]

Exactly. Flektogon 50/4 P6 will have the same angle of view as any other 50mm lens.

The key difference of medium format lenses is that they draw larger image circle to cover the bigger area. But they also collect light from a wider are. So if you use it on 36x24 sensor, the additional light, which is collected to cover the larger field (and which makes the 50mm lens wide on P6 body), is discarded and that's why it perform just like any other 50mm lens

I tried to draw a scheme... hope it helps

[propellor]

Thanks very much for the info. The drawing is very clear. So the main advantage would be that you use the best part of the lens ie, "the sweet spot".

Would the 20 and 35 mm lenses with th m42 mount be an option to complete the range and get the same look and feel as the P6 Zebra's ?

thanks guys.

[peterqd]

no-x, thankyou for your useful diagram! Do you think it would help explain a bit better if you showed the larger back-focus distance for the P6 lens? This is the reason it gives a larger image, I think. The viewing angle for both lenses should be the same. Please tell me if I'm wrong!

[peterqd]

Hello Bart and welcome to our forum!

I can't be as helpful to you on this topic as I'd like to be. Is it your wish to make a collection of "Zebra" lenses or a set of lenses with similar optical qualities?

Someone else will know much more about P6 lenses than I do. The M42 CZJ Zebras went out of fashion in the mid-60s, before multi-coating was invented. The old Zebra f4/20mm and 2.8/35mm Flektogon lenses were redesigned and mostly improved for the later black versions but I think, except for the coatings, the 50mm and 80mm Pancolars and the 135mm Sonnar were the same optics with just a cosmetic change to the barrel.

[sichko]

[peterqd]

[no-X]

The distance between the lens and sensor (film) is same for all cameras. Moving the lens far from the sensor would involve it in the same way as adding an macro extension tube (= it will allow close focusing only).

[peterqd]

[sichko]

[peterqd]

This is all fine but I don't think it has much to do with the comment I made about the diagram. The fact is, if you project an image through a P6 lens onto a white surface, the back of the lens, the mount surface, has to be 74.1mm from the surface for the image to be in focus, and for an M42 lens the distance is 45.46mm, so the image will be smaller. I'm sorry I mentioned it, please let's drop it now.

[propellor]

[PaulC]

You're not going to get the best contrast on a single-coated flek 50. You will probably get a nice result though.

The 50mm flek is quite a big lens, it hardly seems a logical choice for use on a 35mm camera when the manufacturers produce such cheap, good 50mm primes (but I probably don't understand film-makers' needs).

Also the 50mm flek is not fast at all, it is f4.

There is a lot of variability between different flektogon samples and I have some doubts about the claim that the glass of the MC versions is inferior to that of the zebras. Surely that would apply to all Zeiss lenses, and there is no evidence of it that I know.

See http://www.rickdenney.com/mother_lens_test.htm for some info about the variation in these lenses and how they compare with more expensive non-Communist glass.

[Frank Glencairn]

Video, especially HD-Video is an other beast.

A lot of folks try to achieve a softer, more organic film look, to take away some of the harsh oversharpness of video - the medium format Zeiss glass does exactly that.

If contrast and sharpness is what you want, this glass is not for you - but if you want a organic "analog" look with nice blooming and great roll-off in the lights, they are great.

Frank

[Joosep]

The "sweet spot" story is not so simple.

Lenses have resolution power, as does P6 lenses.
Medium format lenses resolution is not very significat, BUT as resolution is measured in mm and the medium format is pretty big, then the quality output is very big.
Now you are only going to use the middle part, the resolution power will stay the same, but as the area will get smaller, so the total quality output.
So after if you would take a picture with a 6x6 and 35mm, with the same lens, then scan and resize to the same size, then 6x6 will have alot more quality, alot.
I would recommend you to go for 35mm lenses. You can get faster lenses for the same price. And because P6 lenses are for a bigger format, they are always bigger than the same focal lenght 35mm lens.

Only reason I see to use these boys, is if you want to do tilt shift or have already got a great collection of medium format lenses.

[spleenone]

I think that you never get organic film look even you use cine lenses on digital video cams. Why? Because film shooting look you can get only one way and that shoot on stock and with movie cam not with anorganic matematic calculating digitals. Although video from those digitals look pretty good speak nothing about superb 5DmkII. It makes wonders. It is true that you can achieve very nice and special character look with old optics as CZJ or old Nikkors (as I do) for example but never ... I think that you never get that lifelike and unique cine film character.

ps. try to shot on HD video camera with CZJ Sonnar 300/4 or Flektogon 50/4. I would like to see you at filmmaiking with such combination otherwise next I would like to try is at least Sonnar 180/2.8. With my Biometar 80/2.8 I felt more than comfortable even handheld.

edit: but welcome Frank

[Frank Glencairn]

[spleenone]

[Frank Glencairn]

Yeah, in theory - I know that.

But look at the pictures - the real world acts different.

The comparison between the 50mm/4 Flektogon
and a 50mm 1.4 Nikon (both at wide open) on my blog.

Actually even I´m not totaly sure what is going on here.
I checked it 3 times, but at wide open the f4/50mm Flektogon is almost as fast as the f1.4/50mm Nikon.

The only thing I can think of is - as you mentioned - a different T-stop because of the huge diameter.

Frank

[berraneck]

the photos on your blog lack exif - just to be sure, is the ISO sensitivity and exposure time same on both pictures?

they aren´t 100% same, the one shooted with flektogon is slightly darker (on my lcd, photoshop says the same), but not by 3stops. theory with T-stop is possible, also maybe some reflections in adapter may cause this? strange:)

[spleenone]

I can try it with my Flek MC 50/4 compare lets say to Nikkor 50/2 ... I am really interested in my results
...but maybe latter. I have some exams now.

edit: yes and T-stop can differ as I know cca about one third or max half number of f-stop. Huge difference is improbable.

[Olivier]

Looking forward your results.
I'm gonna try myself with my own Flek 4/50mm and a Canon EF 1.8/50mm.

[spleenone]

Okay... it's obvious.

Here rear element: hole is cca identical to diameter of aperture; and front which have nothing with speed of the lens. It is design lens factor. In this case 50mm Flek is wide angle compare to 50mm Nikkor which is standart lens.. .





then... Flektogon mc 50/4 at f4 ... 1/80, iso 800



and Nikkor 50/2 Ai at f4 ...1/80, iso 800



and finally Nikkor 50/2 Ai at f2 ...1/160, iso 400


I made it good with my knowledge. Sorry for bad focusing about Flek but that lens is soft WO even at FF. On 120 format have really more and better res. But winner is clear. Nikkor =D
...in this case. Cheers.