Focussing very wide lenses

RobC · Jul 22, 2008

Can someone tell me what happens when you put a very wide lens on a range finder.
For example a 15mm lens on a Zeiss Ikon. I realise the standard finder does not have frame lines for the lens and you need a special view finder for the wide lens, but what about focussing? Does the focus in the built in viewfinder work for the wide lens or do you just rely on short focal length having very great DOF and set hyperfocal distance for your chosen aperture?

Ian Grant · Jul 22, 2008

The normal range-finder works fine, but in practice you can just set the hyperfocal distance and forget about it. I can't speak specifically about the Zeiss 15mm, but that works fine for the Leitz 21mm.

Ian

Tom Hoskinson · Jul 22, 2008

My CV 15/4.5 ASPH Super Wide Heliar is not rangefinder coupled, I estimate the distance and dial it in on the lens scale. The lens has great depth of field. I also have the 15mm finder.

Tom Hoskinson · Jul 22, 2008

My CV Color Skopar 21mm F4 is rangefinder coupled and came with a CV 21mm viewfinder. It has become one of my favorite lenses.

Anupam Basu · Jul 22, 2008

It's just like using any lens with an external finder - like on the Bessa T or the old LTM Leicas. Focus with the RF, frame with the finder. The 15/4.5 CV isn't RF coupled, though. With its DOF, it doesn't need to be. But for lenses that are, this is the drill.

RobC · Jul 22, 2008

Thanks all, I found some more information. The Zeiss ZM 15 lens is not range finder coupled but if you have its viewfinder then you can see some special markings on the lens through the viewfinder which aids in setting focus distance:

Special features
The focusing ring is not coupled with the cameras rangefinder.
Therefore, it is not possible to focus with the
cameras viewfinder. Due to this lens extraordinarily large
depth of field, it is sufficient to set an estimated range.
There are two 1 m and 2 m marks on the focusing ring.
Both marks can be recognized when looking through the
shoe-mount viewfinder. This allows you to simultaneously
set the image section and the standard range.
Example: Aperture 4 and a range setting of 2 m result in
a depth of field range of 1 m to infinity.

Woolliscroft · Jul 22, 2008

You hardly have to focus a 15mm, it has so much DOF. Certainly guessing on the focus scale has always been good enough for me.

David.

RobC · Jul 22, 2008

Now all I need to do is find the dosh to buy it...

Pinholemaster · Jul 22, 2008

I have a 12 mm Voigtlander for my Leica M6. The lens is not rangefinder coupled. Depending on your aperture, you set the focus via click stops in the focus ring. Depth of field covers pretty much everything. With the 15 mm stopped down a few stops, you'll be in focus from a foot or two from the lens to infinity.

Nick Merritt · Jul 23, 2008

Focusing a very wide rangefinder-coupled lens is one of the advantages a rangefinder camera has over an SLR -- seeing the double image is a lot easier than trying to figure out by looking through the SLR lens whether you're in focus (made harder by the fact that really wide lenses are often relatively dim -- f4 or slower). But using the auxiliary viewfinder, with its inherent imprecision in framing, is a disadvantage of a rangefinder camera.

Ole · Jul 24, 2008

The 21mm Color Skopar is the widest of the current CV lenses that is rangefinder coupled. The 12mm and 15mm are not, but the DoF is so large that it's almost unnecessary to focus.

Focussing very wide lenses

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