Medium format lenses

Chris L

Chris L

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Christian
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OK, I know very little about MF and have zero experience of using the kit

I really loved shooting with a 35mm f1.4 and 85mm f/1.4 on a 35mm format (digital) camera. My main question is, what focal lengths and max apertures would I need to get to be able to replicate the same angle of view and DOF of those two lenses on a 645 camera? (probably a Mamiya)

The second question is, what is image quality like from the Mamiya lenses in general when shooting wide open...do they perform in the same way from CA as lenses like the 35 f/1.4L or is it better or worse?

Cheers,

Chris
 
Thanks for the link Mark. I can see I would need a 55mm f/2.8 and the closest I could get to the 85mm f/1.4 on 645 would probably be a 150 f/3.5.
 
+1. DoF decreases (effectively) with bigger formats at a given aperture. There's Google if you're into pointless maths :)
Q2, I can't sat definitively but the vast majority of lenses, of any format, benefit from being stopped down by one, at least. Two better. More than 4, you start getting probs :)
 
TheBigYin said:
running the figures though DOFmaster comes put with the 85 1.4 and 150 3.5 as pretty much the same in terms of DOF.
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Yeah, thanks for that Mark, I'd already run them through and came out with a fairly close 135 format equivalent of 100mm @ f/2.5. Whilst I've seen that there's also a 150mm f/2.8 for Mamiya's 645 there's no way I can afford it!:)

Carter64 said:
+
Q2, I can't sat definitively but the vast majority of lenses, of any format, benefit from being stopped down by one, at least. Two better. More than 4, you start getting probs :)
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This is why I was hoping some people with specific experience of the 150mm and 55mm lenses my be able to offer their opinion. Are the figures you mention "clicks" or full apertures? I'm happy with the quality of the two EF mount lenses wide open but the thought of losing at least 1 or 2 stops on a f/3.5 lens is less than ideal to me.

Mahoneyd187 said:
Medium format lenses.......are ****ing lovely :)
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Do you have specific experience of either the Mamiya 55mm f/2.8 or 150mm f/3.5? :)
 
Nope, I shoot with an RZ67 and I currently only have the 180mm 4.5/

My favourite lens on my Nikon system has been the 85mm prime, and they're very similar in eq length, so it's the one I went for and I love it so far
 
Chris L said:
Are the figures you mention "clicks" or full apertures? I'm happy with the quality of the two EF mount lenses wide open but the thought of losing at least 1 or 2 stops on a f/3.5 lens is less than ideal to me.
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Full 'stops', rather than 'clicks'. Although possibly just a pixel-peeper issue, there's an effect called 'Diffraction Limitation'
I think it's been discussed here before but there's this:http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
For a bit of a read-up :)
 
Carter64 said:
Full 'stops', rather than 'clicks'. Although possibly just a pixel-peeper issue, there's an effect called 'Diffraction Limitation'
I think it's been discussed here before but there's this:http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
For a bit of a read-up :)
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Well worth the read, very well explained! Thanks!

Possibly a pixel-peeping issue but, dare I venture that this might become a point worth considering when very large prints are the thing.

I did think that the 4 stops from fully open was a bit harsh and indeed so but generally stopping down more than f/22 (or f/16 for some) should rather be avoided...or that is my take on it at least...:thumbs:
 
Mahoneyd187 said:
Medium format lenses.......are ****ing lovely :)
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that's about the size of it..

I think we're starting to over think things a little when we think we can apply everything we think is important in our digital kit, to a medium format kit.
First thing I learned was just to forget all that crap because whilst the principles are the same, it hardly matters to any great extent in real life practical use.
If you want a 35mm f1.4 lens to shoot with, stop looking you already have it, but it doesn't exist for an MF system, buy a 50 3.5, shoot it, find out its fablious in its own right, have fun and don't get too bogged down with the digital micro measurement obsession thing...its not like you have a huge choice of lenses from five different manufacturers anyway, you can only use what exists...:)
 
Thanks for the comments guys and point taken about just using them rather than trying to replicate the same focal lengths and DOF :)
 
Look at the DOF scale on, say, a 100mm lens. It is pretty much the same be it 135 format or larger format except on a larger format camera you have to get closer to fill the frame equally and we all know that the closer you get, the shallower the DOF. That is one reason larger format lenses are not f1.4.
 
antonroland said:
Why, if I may ask, please elaborate...

Thanks
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Its because you start getting problems with diffraction and an artefact called 'Airy Disc's', this softens the image and reduces resolution, hence the reason its not best to go to f16 every time for maximum depth of field like some people do, most lenses are sharpest and have the most resolution around the f5.6 - f11 mark. Its better to shoot at f8 or f11 (on 135 film) and scale focus for more depth of field than to automatically just go for the smallest aperture.

Usually stopping down 2 or 3 stops from the minimum aperture will generate maximum resolution and sharpness from a lens but it varies with each type.

That is one reason larger format lenses are not f1.4.
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And how massive they would have to be...
 
s162216 said:
Its because you start getting problems with diffraction and an artefact called 'Airy Disc's', this softens the image and reduces resolution, hence the reason its not best to go to f16 every time for maximum depth of field like some people do, most lenses are sharpest and have the most resolution around the f5.6 - f11 mark. Its better to shoot at f8 or f11 (on 135 film) and scale focus for more depth of field than to automatically just go for the smallest aperture.

Usually stopping down 2 or 3 stops from the minimum aperture will generate maximum resolution and sharpness from a lens but it varies with each type.



And how massive they would have to be...
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When are medium format lenses supposedly at their sharpest? I know it's generally regarded as f8-f11 for 35mm and digital 35mm
 
Mahoneyd187 said:
When are medium format lenses supposedly at their sharpest? I know it's generally regarded as f8-f11 for 35mm and digital 35mm
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its probably around that sort of area too, i rarely use my RB lenses wide open so i cant vouch for how sharp they are at f3.8 and 4.5 respectively
 
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