Voigtlander R3a and Lietz 90mm

[CJP6008]

Dear All,

Does anyone know of any authoritative information as to whether the R3a's rangefinder base (37mm) is sufficient to allow the accurate focusing of fast 90mm lenses such as the Leica 90 f2?

Same question re the accuracy of the entire focusing mechanism in the same situation?

Thanks
CJP

 

[rover]

Based on the Puts, a EBL of 40.5mm is necessary to accurately focus a 90/2 lens.

http://www.imx.nl/photosite/leica/technics/rfaccuracy.html

 

[hamsong]

I can get accurate focus on the 90 Summicron with my M7 .85x, but with the R3a, I think the CV 75f2.5 is your best bet. The advantage the R3a has over the M series, in this regard, is that the 75mm framelines are solo and easily seen rather than the little hash marks inside the 50mm lines... I've had success shooting the R3a with 75mm at f2.5 as long as the subject isn't moving!

 

[CameraQuest]

a 90/2 lens focuses just like a 90/2.8 or 90/4 lens, when stopped down to 2.8 or 4. No, the R3A can not consistently focus a 90/2 lens wide open and closeup. But stop that same 90/2 it down to f/3.5 or smaller, and the R3A can focus it accuragely and consistently.

On the other hand, from about twenty feet out the R3A will also focus the 90/2 accurately wide open at f/2.

In other words, RF accuracy DECREASES as the lens is opened up, or as the lens is focused closer, EVERYTHING ELSE being equal. You can still use the 90/2 on the R3A or R2A or R2, just use the lens within the limits of the rangefinder.

Stephen Gandy

 

[Toby]

If you are shooting portraits it's not really practical to shoot at f2. even if the range finder is accurate the tiniest movements by yourself or your subject will put the frame out of focus if I'm comissioned to do a portrait I use 67 with 165 2.8 at close up I habitually shoot at f11-22 if I want to return 100% sharp photos, at f22 the d.o.f. is still only 10cm at f2 on a 90mm the d.o.f. is probably 0.5 to 1cm you will still get blurry frames no matter what camera you use. Best to stick to f4 as an absolute minimum

 

[Fred]

I agree with Toby, even F4 is pushing it for the full face to be in focus, I'd lean towards F5.6.

As for the suitability on a Bessa, CameraQuest sums it up very well.

 

[peter_n]

Pretty amazing to see a post from Stephen, I didn't know he was a member. Now I'm glad I said nice things about him here... 😉

 

[back alley]

he comes by infrequently but it's always a welcome visit.

joe