National Portrait Gallery

[dennis]

This portrait was taken on 8x10 with a 240/5.6 Rodenstock lens @ 5.6, focussed on the model's right eye. If it opens? Sorry my effort at adding an image did not work. Dennis.

[Charles Twist]

For the image you need to put the URL between image tags, so where it says url here: [img]url[/img]
Charles

[Andrew Plume]

I can't say I've ever tried to do portraits but it's amazing how little depth of field you have with something like an 600mm F9 Apo Ronnar shot at near 1:1 I'm usually doing scarey things with tilt in the 20 to 30 degree range to get more in focus.

Process lenses like the 600mm Apo Ronars and Apo Nikkors seem to have declined in value quite sharply over the last few years I paid about 300 for a mint boxed one in 2008 and have seen examples go for less since then. They are very sharp and could possibly give the result you are looking for if you have a suitable camera to take them.

You're right, Clive, prices for these 'process lenses' have fallen considerably, ok, they're not fast, will not display any bokeh or scarcely any but for the ULF shooters, they're dead cheap

regards

andrew

[timparkin]

I am however far less comfortable re your equivalent f stop ratios.

Why less comfortable?

Tim

[Charles Twist]

Because I don't know the theory well enough but it doesn't feel right to say that the f/stop should be divided by 4 as well. Is the dof related to the physical aperture or to the f/stop?
Thanks,
Charles

[dave_whatever]

I believe dof is related to the size of the physical aperture, so hence it is scaled with the focal length/diagonal. I've probaky not explained that very well, but Tim is basically right with the theory there.

So the factor of 4 used to scale it is right (or as I use, 3.5, since to me the diagonal governs the overall feel of width regardless of format, and I doubt its safe to assume that anyone shooting 35mm routinely crops down to a 4x5 ratio).