Need an education in manual focus w/ mfd

[Alex MacPherson]

I am doing a shoot this weekend with my newly acquired
Hasselblad 553ELX and Phase One P30 back.

It is going to be people. In some of the shots, there will be someone in the foreground, middle and background. Where
should I be putting the sharp focus? (I have a 4x4 DPS magnifyer). I want all 3 subjects to be in sharp focus. I will be shooting with a 60mm CF lens.

I understand the depth-of-field scale but there is a 1.3 lens multiplier with the sensor.

I half remember hearing that using depth of field doesn't really work that well with mfd.

Can someone give me some pointers?

[John R Smith]

Alex

There have been many discussions already on this very subject. My thoughts are here -

http://www.luminous-landscape.com/forum/index.php?topic=43636.msg365770#msg365770

In my own experience, the 60mm Distagon is quite a tricky lens to use on a MF DB. The 80, 120, and 150mm all "pop" into focus rather nicely, whereas the 60 and 50mm do not. And they are Distagons, which means that they are optimised for infinity, not the near-field. Performance falls off markedly when focused closer than 12 feet or so, particularly when used at wider apertures than f11. Although in theory the greater DOF should compensate for this, in practice I can often get a crisper shot with the 80mm when working close.

John

[Rob C]

All lenses, of all focal lengths, have the same depth of field at the same aperture and magnification.

The rule of thumb is: there really is no depth of field, just progressive deterioration which, with digital, seems to be even more marked. The rule printed on the other thumb tells you to focus a third of the way into the scene, on the principle that there is more imaginary depth of field behind the plane of focus than there is in front of it.

Solution? Try multiple shots, if static scene, or stick the people fairly close together and pray. Film would help because you could stop right down with less (?) deterioration.

In an ideal world, that's where camera movements would help you out.

Rob C

[fredjeang]

And the scale is real.
Try this: shoot a physical painting that you know the size in cm with different lenses.
lets say that your painting measures 1m x 1m

whatever lense you use, and whatever scale you apply in PS, if you put a mark on strategic point of your digital image, and measure it with the photoshop ruler the X and Y, it will correspond exactly to the physical points location in the real object.
Of course, I'm talking about different lenses at the same magnification.

You can verify that with physical buildings for example that you have the arquitecture drawings. You'll find exactly the correct dimensions, but you need to be on the same parallel. That's why it's more easy to verify with small objects.

[Alex MacPherson]

Thanks guys. I will do some testing before the shoot. I don't want
any surprises. ;-)

[rschmid]

It's also important to get your Hasselblad adjusted with your back because the tolerances are so tight.