So I have some Mamiya 645 MF prime lenses at my disposal and was wondering what some of your opinions are on whether or not I should invest in a $100 adapter for them? Of course the iris would be controlled by the lens ring, but the focus on these guys is as smooth as butter and has hard stops! Any opinions?

I decided to go ahead and order the adapter, even if the lenses only work out for playing around with. I'm sure that they will be adequate for shooting video? At least I'll be able to pull some super smooth racks with them. As soon as I get the adapter I will be running some tests on a 150mm/3.5, 80mm/2.8, and a 70mm/2.8. These are all lenses from a Mamiya 645 Medium Format film camera so it will be interesting to see how they hold up on the full image sensor of the 5DII.

Ahh...I used to have a 'Mami 645'.
Won't the lenses only being using the centre prortion of their image when on a '35mm sensor' like the 5D2?
I love the using the tiny Olympus OM1 lenses on the 5D2 but beware that adaptors can sometimes be a rather poor fit. Both my OM-EOS adaptors (cheap ones admittedly!) have required 'schimming' by putting a piece of tape between the lenses and adaptor.
You'll be getting the Fotodiox 645-EOS ones I guess?

DaveT

David, you might find that your 'cheap' adaptors for the Olympus lenses already have an expandable cut in them to improve the fit. To the best of my recollection there were two or three little split metal sections inside the adapter which could be gently expanded with a small screwdriver, trial and error fashion, to tighten the fit.

I'm attaching an image sent to me by my vendor with a green arrow indicating the split metal area used to improve the fit.

Ahh...I used to have a 'Mami 645'.
Won't the lenses only being using the centre prortion of their image when on a '35mm sensor' like the 5D2?
I love the using the tiny Olympus OM1 lenses on the 5D2 but beware that adaptors can sometimes be a rather poor fit. Both my OM-EOS adaptors (cheap ones admittedly!) have required 'schimming' by putting a piece of tape between the lenses and adaptor.
You'll be getting the Fotodiox 645-EOS ones I guess?

DaveT

Not sure about only using the center of the glass on a 35mm sensor, but I guess I'll find out soon enough. Yes, I will be using the Fotodiox adapters. People have been saying some pretty good things about them. I'm also contemplating a Mirex tilt-shift adapter for these lenses if all goes well.

I will be curious to see how these work out.... Anyone have a Kowa 6 to EOS lens adapter out there ? I have had one of those with three lenses since the early 70's......

I have KAWA from ebay to adopt my nikon lenses, cheap, but unexpectedly good quality,
I have a few of them and just keep them on the lenses, of course it works for manual lenses only.

I have KAWA from ebay to adopt my nikon lenses, cheap, but unexpectedly good quality,
I have a few of them and just keep them on the lenses, of course it works for manual lenses only.

Different Kowa... Kowa 6 was a 2 1/4 camera in 70's that was supposed to try to compete with Hasselblad... Had some great lenses and great images, but their camera body had some mechanical issues making it less than reliable. Mine still operating fine, but that is why it never caught on professionallly..

I finally got a chance to do some testing with the Photodiox adapter and the Mamiya 645 lenses and am quite shocked at the results! Just a refresher, I tested a 70mm 2.8, 80mm 2.8, and a 150mm 3.5. The 70 and the 150 are a little soft and I probably wouldn't use them for still photos, but work pretty well for video. The 80mm however is a different story all together! Super sharp at any aperture. It is even more sharp than my 50mm 1.4 (non L) Below is a 21mp shot through the 80mm that has been cropped at 100%. I just added another one shot with macro filters. The one of the fly is cropped to 66%. Both of these were shot without sticks.

All of the focus rings on these lenses are extremely smooth and virtually free of any noise. I will be using the 150mm primarily for a moderate telephoto for rack focuses as it is smoother and much easier to pull focus with than any of my Canon lenses. The Mamiya's have hard stops too woo hoo! Great for using with a follow focus.

I never thought that medium format lenses would fair so well on the 21mp 5DII.

My hat goes off to the people at Fotodiox as well. The adapter is solid and looks very professional. Shipping was fast too.

Wow, Ryan, that looks amazing, what shutter speed? With out sticks did it have to be rather high?

Thanks Dutch! Yes the shutter speed was set fairly high on both of these shots. The bee was at 1/1250 and the fly at 1/800.

Anyone have a Kowa 6 to EOS lens adapter out there ?

I've just ordered a Pentacon 6 tilt adapter and a 90mm Vega 2.8 lens to accompany it.

The lens was $50, the adapter $115!

EDIT: Ryan, I'd be very curious to know more about the breathing behaviour of the lenses you purchased. I'm looking for an economical lens that doesn't breathe

The 150mm is minimal while the 80mm is pretty moderate. Check out the test clips below. They are pretty quick and dirty so I wasn't really concerned with getting them teribly smooth. Just testing the breathing.

So I have some Mamiya 645 MF prime lenses at my disposal[...]
How does the aperture compare when a medium format lens is mounted on a 35 mm body? I understand the crop factor with respect to the focal length, but how does it affect the equivalent aperture and depth of field? Naïvely it would seem that the aperture would increase by the same factor: a MF 80 mm f/2.8 lens would have a physical aperture of 28 mm, but since the equivalent focal length is now 170 mm, does this mean that the aperture is equal to f/6?

How does the aperture compare when a medium format lens is mounted on a 35 mm body? I understand the crop factor with respect to the focal length, but how does it affect the equivalent aperture and depth of field? Naïvely it would seem that the aperture would increase by the same factor: a MF 80 mm f/2.8 lens would have a physical aperture of 28 mm, but since the equivalent focal length is now 170 mm, does this mean that the aperture is equal to f/6?

Yes! You got it exactly right. The "crop factor" applies to f-number just as much as it does the focal length. For example:


50mm on 35mm (36x24mm) has an AOV (horizontal angle of view) equivalent to 83mm on MF-645 (Medium Format 60x45mm).
25mm on Four Thirds (18x13.5mm) has an AOV equivalent to 50mm on 35mm.
8mm on a Digicam (6x4.5mm) has an AOV equivalent to 50mm on the 5D2.


The same exact thing applies to f-number for equivalent DOF (for the same bellows factor):


50mm f/4 on 35mm has DOF equivalent to 83mm f/6.7 on MF-645.
25mm f/2 on Four Thirds has DOF equivalent to 50mm f/4 on 35mm.
8mm f/2.8 on a Digicam has DOF equivalent to 50mm f/16.8 the 5D2.


It also applies to diffraction. For example, these all have the same exact amount of diffraction:


8mm f/2.8 on a Digicam
25mm f/11.7 on Four Thirds
50mm f/23.4 on 35mm
83mm f/39.0 on MF-645.


It also applies to the total amount of light with the same luminance and shutter speed. The larger formats have lower intensity of light per area, but they have more area, so the total amount of light comes out the same in the end. If you can increase luminance or integration time, then the larger formats will get more light, even with the narrower f-number.

Though it does make sense that there would be a crop and aperture issue when using MF lenses on the 5DII, I have not noticed any issues in the slightest. See my examples below:

This one is shot with the Mamiya 80mm at f2.8, shutter speed 120, and ISO 100-
http://www.rpmproductions.info/pics/mamyia_80mm.jpg

This one with the 50mm Canon from the same exact location at f2.8, shutter 120, and ISO 100-
http://www.rpmproductions.info/pics/canon_50mm.jpg

and this one was shot closer to the subject to the subject to compensate for focal distance. It was shot at f2.8, shutter 120, and ISO 100-
http://www.rpmproductions.info/pics/canon_80mm_closer.jpg

From what I can tell there doesn't appear to be a crop factor or a relating effect on aperture. Maybe someone that is more experienced than I with dslrs can see something that I am not.

From what I can tell there doesn't appear to be a crop factor or a relating effect on aperture. Maybe someone that is more experienced than I with dslrs can see something that I am not.

The "crop factor" does not change physical properties of a lens. All 50mm f/2.8 lenses will have the same angle of view a Four Thirds camera, no matter what system they were made for: Four Thirds, APS-C, 35mm, or Medium Format. For example, these all have the same exact angle of view, depth of field, and diffraction:


Olympus 50mm f/2.8 on a Four Thirds Camera
Canon EF-S 50mm f/2.8 on a Four Thirds Camera
Canon EF 50mm f/2.8 on a Four Thirds Camera
Mamiya 50mm f/2.8 on a Four Thirds Camera


Even if the lens was made for Medium Format (e.g. 645), when you put it on a smaller format (e.g. Four Thirds), the focal length and f-number do not change.

So even though a lens does not change when it used on different formats, the resulting picture does. And it helps to understand when the resulting picture is equivalent. That is where crop factor comes in.

[QUOTE=Ryan Mueller;1277645]The 150mm is minimal while the 80mm is pretty moderate. QUOTE]

Many thanks. Both seem to have significant breathing issues. The search continues.