Can someone help explain wide angle lenses + M8 framelines please

[andrew00]

Hey,

So I'll start by saying I'm an idiot who has tried to learn about this but not really understood it, so sorry if I'm covering old ground.

I'm basically looking to understand M8 framelines and the crop factor.

I'm trying to figure out what is the widest natural lens (aka no external vf) I can have on an M8 and see framelines that are accurate for it.

Where I'm confused is if the framelines are crop adjusted before or after.

I.E. if I want a 28mm equiv, do I put a 21mm on it and then see 28mm framelines b/c 21*1.33 = 28mm? Or does it work differently than that?

Thanks!

 

[Lss]

I'm trying to figure out what is the widest natural lens (aka no external vf) I can have on an M8 and see framelines that are accurate for it.

The widest framelines are for a 24mm lens.

Due to the crop factor, this lens has a field of view equivalent to a 32mm lens on a film Leica or a later digital Leica. The lens is a 24, the framelines are called 24, the field of view is that of a 24 on an M8 (and equivalent to a 32 on fullframe). Leica obviously knew about the crop factor when building the camera, and the framelines are therefore designed accordingly. The easiest clue is that the nominations correspond to existing Leica lenses.

I.E. if I want a 28mm equiv, do I put a 21mm on it and then see 28mm framelines b/c 21*1.33 = 28mm? Or does it work differently than that?

Let's say that you will see and use 35mm framelines, when you mount a 35mm lens (assuming M mount or correct adapter). The crop is taken care of for you.

The 21mm lens is a little more confusing as there are no framelines for this particular focal length. The widest you have are for a 24mm lens. So, you pick a 21mm lens for your desired field of view. However, the camera does not have correct framelines (21) for it. In this case you may use the entire viewfinder to approximate, or you may pick an external viewfinder. The problem is that the external viewfinder does not know about the crop. Now you need to do the math yourself, and pick an external 28mm finder. There are also some crop factor viewfinders out there. Those usually have a "fullframe focal length" and a "crop factor focal length" marking (which may or may not correspond to the one on M8).

 

[andrew00]

Thanks for the reply.

So, to confirm if I've got it right, in all cases the first thing is to consider the crop.

So, if I want to be around 28mm then I should get a 21mm as that'll give about a 28mm in the M8.

Then, for the framelines, the camera will adjust to what I'll get if it can, so if I put a 35 on it, it'll show a 35 when cropped by 1.33.

But where I'm adding something that doesn't have natural frame lines, as in the 21mm, it can't compensate as it's too wide naturally, but I can make my own manual compensation, aka just use the VF as my frameline?

 

[jsrockit]

So, if I want to be around 28mm then I should get a 21mm as that'll give about a 28mm in the M8.

Yes, and then use an external 28mm VF.

 

[Ong]

Thanks for the reply.

So, to confirm if I've got it right, in all cases the first thing is to consider the crop.

So, if I want to be around 28mm then I should get a 21mm as that'll give about a 28mm in the M8.

Then, for the framelines, the camera will adjust to what I'll get if it can, so if I put a 35 on it, it'll show a 35 when cropped by 1.33.

But where I'm adding something that doesn't have natural frame lines, as in the 21mm, it can't compensate as it's too wide naturally, but I can make my own manual compensation, aka just use the VF as my frameline?

You got it.
Basically the framelines are already compensated for crop factor. So don't worry too much about that.

As for the 21, from my experience I just used the whole viewfinder (give or take a few mm on the side due to parallax) as a rough guide of the framing. It will bring up framelines just due to the nature of the mount, but for all purposes ignore them.

 

[Ronald M]

Mount a 21 and 28/90 come up just as any other Leica M. More narrow view angle is automatic.


The only difference to a full frame M is a 35/135 is a 24/35 with the narrower angle from crop sensor are 32/35

 

[jaapv]

It helps a lot if you realize that the focal length of your lens will remain the same. A 21 mm lens cannot change into anything else suddenly. However, the angle of view is different, just like cropping the final image. Hence the name Crop Factor. The crop is incorporated in the viewfinder framelines. So just use your lenses as you see them in the viewfinder and forget about the numbers. As people said, use the full viewfinder for an approximation of a 21 with the angle of view you are used to on a 28. One week and you will have forgotten that it ever was a problem.