25mm lens & 35mm frameline

[teastman]

Hi, how accurate are the 35mm framelines on the r-d1s with a 25mm lens? are they more accurate with a 28mm lens? I generally focus around 1-2m.

Tim

 

[Jim Watts]

The R-D1 framelines are adjusted for the 1.53 crop factor.

The 35mm framelines in the R-D1 are closer to the field of view of a 40mm lens than the nominal 35mm (53mm equivalent) lens because of the 0.85x safety factor.

If you do not wear glasses and can see the whole of the R-D1 finder area beyond the framelines this is a pretty good match for a 25mm lens (no parallax correction of course). Otherwise any 35mm external viewfinder for fullframe 35mm film should work fine for a 25mm lens (38mm equivalent on the R-D1).

 

[teastman]

I'm confused-a 25mm lens is equivalent to the entire rangefinder window, but is also equivalent to 38mm?

 

[RML]

For my CV 25/4 I simply set the framelines to 28mm. That already gives me a good indication of what will be in the shot. If I need more accurate placement, I use the entire view finder.

 

[Jim Watts]

I'm confused-a 25mm lens is equivalent to the entire rangefinder window, but is also equivalent to 38mm?

YES.

Because the framelines in the R-D1 viewfinder are adjusted for what the field of view will be for a camera with a 1.53 crop factor. i.e. the lens only gives its normal angle of view on when covering the area of a 35mm frame of film. The area of sensor covered by the R-D1 is smaller than that size (by 1/1.53 times) so it is as if you are enlarging the middle part of a 35mm film (or full frame sensor) frame. Therefore the field of view the sensor sees would be the same as if you were using a longer focal length lens on a full frame camera. The 28mm frames = 42mm, 35mm frames = 53mm and 50mm frames = 75mm.

All this is slightly more complicated by the 'safety factor' (as stated previously) used to avoid any possibility of cut-off due to parallax.

Therefore 25mm lens (really the equivalent of a 38mm lens on the R-D1)just about = the full area of the viewfinder.

 

[teastman]

ok, I understand-just how closely does the what appears on the negative w/ a 25mm lens correspond to what the viewfinder shows?

 

[Jim Watts]

ok, I understand-just how closely does the what appears on the negative w/ a 25mm lens correspond to what the viewfinder shows?

Negative? I assume you mean R-D1 sensor in this case? As previous messages if you don't wear glasses and can see the whole of the R-D1 viewfinder area, then that's a fairly good match to a 25mm (38mm equivalent) lens on an R-D1. As RML suggests the 28mm framelines can be used 28mm = 43mm (equivalent) x 0.85 safety factor = 36.5mm, but these are a bit tight for a 38mm (equivalent) lens and you will almost certainly get some cutoff at the 1 - 2 metres suggested in your first post. A lens effectively increases slightly in focal length as you focus closer.

A rangefinder camera is never going to give the accurracy of an SLR where you are viewing through the taking lens.

The best (and easiest course) is to make a few comparisons yourself to see what is acceptable to you by comparing what you see in the viewfinder at various distances with what appears on the LCD of the R-D1.

 

[teastman]

ok, thanks a lot for the information, this has all been really helpful

tim