canon ae-1 diopters?

[bardamu]

So, being a +1.5 reading glasses user, I've read that the camera default screen is -1 and got a +0.5 diopter.Also got a +1. Now if I slip on the diopter the vision gets blurry, basically never getting in focus. Are these meant to be added to the default screen or am I missing something? Thanks

 

[Chan Tran]

If you are +1.5 reading glasses user you probably do not need any diopter. The -1 specification meant that the image in the viewfinder appears 1 meter from your eye. You should put the diopter that give you good vision at 1 meter. I am not sure how Canon specify their diopter but Nikon would call the +1 lens diopter as 0.

 

[bardamu]

Coming from the Bronica GS1 and the Mamiya RZ67, where you replace the default diopter with the one that matches your sight, with both starting around -1 to -1.5, I am now very confused. I have shot one roll with the default Canon diopter but it seems to miss focus by a touch (the "tip of the nose instead of eyebrows" kind of thing).

 

[ciniframe]

Some questions first. This missed focus, how are you checking it? By looking at the negatives? Don't trust prints, always examine the negatives. Another consideration, does the screen focus agree with focus at the film plane. If it were me I'd check that first. (although in a AE-1 I'm not sure what to do about it if the screen or mirror is not sitting in exact alignment.) I believe Chan Tran is correct. Most camera makers set 35mm SLR eyepiece viewing distance at 1 meter. You could go to your eye doctor and get a prescription for viewing at 1 meter and then try to match that diopter.

 

[AgX]

see for diopter designations here:
https://www.photrio.com/forum/threa...-diopter-my-eye-is.158811/page-2#post-2064611

Canon applies the system described in -1), with the finder having -1 diopter.

 

[bardamu]

Some questions first. This missed focus, how are you checking it? By looking at the negatives?

These negatives were scanned, below an example, shot maybe at f1.8 - 1/125 sec without any additional diopter

 

[AgX]

So, being a +1.5 reading glasses user, I've read that the camera default screen is -1 and got a +0.5 diopter.Also got a +1. Now if I slip on the diopter the vision gets blurry, basically never getting in focus. Are these meant to be added to the default screen or am I missing something? Thanks

As Chan Tran said, you are overdoing things.
For instance needing reading glasses of 3.5 diopter means needing to add a lens of true 1.5 diopter to the AE-1 to gain max. screen sharpness.
This should be the same as adding a Canon attachment eyepiece designated 0.5 diopter.

(I never got a Canon attachment eypiece at hand, so I can't check.)

 

[bardamu]

Sorry but I just don't get it.
I understand the system is additive, so when I put on a +0.5 attachment I get a -1+0.5 system, when I put on a +1 I get a -1+1 and so on. If I need to add until I reach my +1.5 prescription, this means I need a +2.5 attachment.
No?

 

[Chan Tran]

First of all I don't think you need +1.5 to see well because you can see well with +1.5 at about 12 inches. At 39 inches you need either none or about -0.5 to see well. As I said I don't know about Canon way of labeling their diopter. With Nikon if I buy a -0.5 lens it's actually +0.5 lens and when put on the viewfinder the total is -0.5.