Lens size equivalent for Hasselblad to Nex question

The crop factor is 1.5.

Another question is , apart from fun, why do it. A lens designed for medium format will not have the resolving power of a lens designed for FF for the simple reason that it doesn't have to. The magnification levels of medium format relative to FF or aps is negligible so the circle of confusion is less critical -as are aberrations.

This is one of the reasons it's hard to make a really good aps sensor lens - the resolving power has to be 2.5 times that of a FF lens to match it. Not going to happen. That's why -as good as aps can be - and I think sony is one of the best - it will never trump FF when it comes to absolute resolution.

All I'm saying is that the Hasselblad lens that's so great on a Hasselblad, may very well be mediocre on an aps sensor. I'll be interested in hearing about the results.

probert500 said:

The crop factor is 1.5.

I'll be interested in hearing about the results.

Click to expand...

OK, I will bite. Don't kill the messenger.

NEX-7, 1/1600s, ISO400, handheld, sunny, windy, around noon. Hasselblad CZ 250mm CF, wide open f/5.6. Fotodiox HB -> EOS, EOS -> E adapters. RAW converted to JPG with ACR. Minimal post processing. No color management manipulations.

1. Original photo, resized for upload





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2. 100% crop





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3. 200% crop





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Thank you for viewing,

Steven
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no one needs to get hurt. Here the low contrast is really working for you - a very formal composition. Funny thing about that lens - I have one - is that it's only so so on the hasselblad. Looks nice here.

pwmoree said:

The Hasselblad 350mm lens I can aquire was made for a 60x60 mm film

FF (full frame) is usually meant to be the old standard 35mm film (actually 24 x 36 mm). This is why we say that our NEX APS-C sensor gives a 1.5 cropfactor compared to 35 mm FF.

What is the cropfactor with the Hasselblad?

Click to expand...

Simple question, simple math.

The diagonal of a 60x60 format is 84.85mm. The diagonal of a 24x36 format is 43.27mm. Thus, the crop factor is 0.51 and your 350mm lens has the field of view of a 178mm lens.

However, if you are used to a square form factor, arguably the full-frame 135 format should be considered 24x24. Maintaining the square aspect ratio, the crop factor is 0.4, making 350mm give the field of view of 140mm on full frame.

Basically, your 350mm will feel a little tighter than a 135mm lens on full frame.

Of course, DOF is different; crop factors are just about view angle.

Oh yes -- if you're trying to see how much tighter that 350mm lens will feel if you mount it on an APS-C sensor as compared to using it on your Hasselblad, just divide 1.5 by 0.51 or 0.4. Your 350mm will give an APS-C view angle like a lens somewhat over 1000mm on the Hasselblad.

I don't think a lens is conscious of what size and shape the film/sensor is. 350mm (non telephoto) is 350mm away from the sensor/film when focused at infinity - that's it.

On a sony aps sensor the equivalent is 1.5 x 350= 525mm.

probert500 said:

On a sony aps sensor the equivalent is 1.5 x 350= 525mm.

Click to expand...

1.5x is for APS-C compared to 135 full frame. The comparison here is with a 6x6cm Hasselblad.

Compared to a Hasselblad, the APS-C crop is 2.94 (or 3.75 if you constrain the crop to have the Hasselblad's square aspect ratio). Thus, the 350mm on APS-C will give a view angle similar to a 1000mm or 1300mm on the Hasselblad.

...measure and report here the size of HB (or other MF) lens[es]
entrance pupil - a passably good approximation of a lens diameter
wide open - together with their FL and max. aperture?

jpr2
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