wjlapier
Well-known
Just curious how to think of what the effective focal length or angle of view would be for some medium format lenses I have. M645 Mamiya 55/2.8, 80/2.8 and 150/3.5. Using two adapters--Mamiya/Nikon and Nikon/Sony NEX. Either NEX 6 or 7.
Thanks.
Thanks.
They will provide the same field of view as any lens with the same focal length, but with a larger (unutilized) image circle.
I.e., the 55mm will provide a field of view just like a 55mm from a 35mm camera will provide.
I.e., the 55mm will provide a field of view just like a 55mm from a 35mm camera will provide.
ColSebastianMoran
( IRL Richard Karash )
Yup, your 80mm Mamiya lens will shoot like a 120mm on 35 or like a longer lens, maybe 200mm (I don't know the ratio) on your M645.
sevo
Fokutorendaburando
The focal length stays exactly the same as written on the lens. It does not change by changing the image format. So that 55 would be a 55, and so on - on APS-C, it has the same angle of view as a 85mm on FF (or a 150mm on 6x4.5cm)...
If you own small format lenses of identical focal length, speed and generic type, you might not want to bother. The small format lenses will usually be just as good, but much less heavy. Medium and large format lenses usually have quite similar lp/mm and contrast specs as any equally professional small format film era lens - the benefit is in the extra coverage giving higher contrast and resolution over the total larger image. Which you don't make any use of if you already crop the centre 24x36mm (or, worse, APS-C) in-camera.
That said, it is perfectly valid to use medium format lenses wherever you have no small format equivalent of them. I sometimes use a Mamiya to Nex adapter for the Mamiya macro, shift and soft lenses - but after I got the A7, I quit doing that on the Nex, the area loss is a bit too big there, and haze issues (due to the vastly excessive image circle) were frequently occurring especially in macro.
If you own small format lenses of identical focal length, speed and generic type, you might not want to bother. The small format lenses will usually be just as good, but much less heavy. Medium and large format lenses usually have quite similar lp/mm and contrast specs as any equally professional small format film era lens - the benefit is in the extra coverage giving higher contrast and resolution over the total larger image. Which you don't make any use of if you already crop the centre 24x36mm (or, worse, APS-C) in-camera.
That said, it is perfectly valid to use medium format lenses wherever you have no small format equivalent of them. I sometimes use a Mamiya to Nex adapter for the Mamiya macro, shift and soft lenses - but after I got the A7, I quit doing that on the Nex, the area loss is a bit too big there, and haze issues (due to the vastly excessive image circle) were frequently occurring especially in macro.