What dipoter do I need?

[Beemermark]

So the eyepiece that is marked -1.5, when removed: is it plane glass, or is it a positive piece of glass or is it a negative piece of glass?

My guess is that it's strongly positive, and not a -1.5 piece of glass. In that case, it's probably like the situation I describe in post 10 above.

I think you are correct. That and the fact that the standard eyepiece @ -1.5 is correcting for a distance of about 2 or 3 feet (1 meter). Unfortunately I've read everything I can find on the manuals and internet and it gives no glue what eyepiece you really need.

KEH just got a -2.5 eyepiece in and I've been trying to call them to get their advice.

I've had this outfit for years, it's just the onsite of old age that requires a different diopter.

 

[Rob-F]

I've had this outfit for years, it's just the onsite of old age that requires a different diopter.

Aha. You didn't tell us that. So the camera is fine for anyone with normal vision? This would imply that you just need to add more positive power to correct presbyopia. Like a +2, as you have been doing. So like I wrote a while back: +2 -1.5 = 0.5.

Like all of us of "a certain age," you have lost your ability to accommodate. Try a +0.5 diopter.

 

[kbb]

Sevo's point is that the power marked on the eyepiece may not refer to the eyepiece itself, but to the eyepiece + prism; thus, the final, or effective, power with the eyepiece in place. For example, a Nikon finder has a native power of -1 diopter, even with no eyepiece in place. So the standard eyepiece, which is window glass, gives an effective power of minus 1, which is what most people need. The reason is that the Nikon finder presents the image at a virtual distance of one meter. A minus one diopter power will allow an eye that is corrected to infinity (normal eye) to focus instead at one meter, where the finder image is.

All this would be accurate if you change "minus one diopter" in the last sentence to "plus one diopter".

 

[sevo]

(1) The AE II eyepiece (when removed) is labeled -1.5
(2) The AE standard eyepiece (per the manual) is -1.5

Depending on how Bronica labelled their eyepieces, that can only mean two things: Your camera is set up for a apparent finder distance of 0.66m. Or in addition to the above it has been fit with a corrective eyepiece for a myopic person needing another -1.5 on top of that.

(3) A combination of the -1.5 eyepiece AND my +2.0 strength reading glasses allows me to focus clearly with my normal 20/20 distance vision. Without my reading glasses things are a little blurry (just like trying to read a book without my reading glasses).

That sounds like the former - a -3 view would be perceived as rather more than just a little blurry, if you need reading glasses at 3ft/1m.

(6) If I remove the eyepiece everything is nothing but a blob of light. If I add +2, +3 or + 4 it remains a blob.

Ok, so they give a cumulative strength, and even a "neutral" eyepiece is a pretty strong optical element, so that the finder is useless without it.

To find a non-Bronica substitute that fits your current (presbyopic) vision, you'll have to find out the true focal length of your current eyepiece, and add your reading glasses strength to that value. If the eyepiece is convex, you may use a projected image of the sun on a wall to measure the focal length - the dioptre is the reciprocal of that distance in metres. If it should be concave, ask an optometrist...

Just hope that their eyepieces are indeed lenses (or achromatic doublets at the very worst), and not some more complex optical group - the latter might be impossible to substitute (at any rate at a price that would not buy you a Hasselblad kit).

 

[john_s]

So the eyepiece that is marked -1.5, when removed: is it plane glass, or is it a positive piece of glass or is it a negative piece of glass?

My guess is that it's strongly positive, and not a -1.5 piece of glass. In that case, it's probably like the situation I describe in post 10 above.

Take the removable eyepiece off the prism finder. Is it a fairly powerful magnifier?

 

[dpt2014]

Diopter

Diopter

I do not use contacts and I am near sighted. I believe my prescription is -1.5 on each side (that was 2 years ago, it's probably worse now).

I just want to make sure before purchasing that Leica diopters are graded like eye glasses. Since my last prescription was -1.5 bilaterally and I think my vision is slightly worse now, I think I need Leica's -2 diopter - is this correct?

Here is what I am looking at: http://www.bhphotovideo.com/c/product/30060-REG/Leica_14358_2_0_M_Diopter.html

Also, does replace the eyepiece on my M3 or does it screw onto it somehow?

 

[sc_rufctr]

The magnification of -2 would be right but these are designed for the newer Ms (M6 and newer) They screw in. I'm not sure how you'd get one onto an M3.

Maybe a camera tech could modify your M3 with some newer M6 parts so you could use one. The diopter wouldn't replace he eye piece. It simply covers it.

 

[dpt2014]

Peter, thanks for your response. I wasn't aware those were designed for later Ms as it doesn't specify.

Based on a couple threads I've read on other forums, correctional diopters do exist for the M3, no?

 

[sc_rufctr]

I've never seen a correction diopter for an M3. They may have existed at some point but I would imagine they would be very rare now.

As I posted earlier it may be easier to get yours modified to accept the current one.

 

[dpt2014]

Just found this, but it's something I'd have to save up for after just having my M3 overhauled. :/

http://walterrxeyepiece.com/camera/leica-m3/

 

[john_s]

Just found this, but it's something I'd have to save up for after just having my M3 overhauled. :/

http://walterrxeyepiece.com/camera/leica-m3/

If your prescription is only spherical, you don't need the rotating function, necessary for people with astigmatism (which shows on their prescription as "cylindrical" correction).

I had an M3 briefly and I remember there was some doubt about threads on diopters. They screw into the existing eyepiece but I think some had a different thread although they were the same diameter. Maybe some M3 have the current thread and older ones a different thread, i really don't know. What I do know is that when I sold my M3 back to the dealer he had to exchange the diopter for a more recent one for the M6 that I bought from him. Sometimes the thread is not so important if the number of threads is shallow, as it is with some filters and diopters. I would try a current style diopter very gently to see if it fits.

I need -1.5 but used to use -2 on my M6. As one gets older (60+) the shortsighted eye often slightly corrects. In my experience (short sight only) less correction is better than too much. Trial and error is the best way to test. Spend some time focusing in poor light (where your eye has less depth of field/focus).

 

[burancap]

I have been down this road. All M diopters are the same! M3 to the 240, I have moved them freely between all M's. There is no modification -they simply thread into the existing eyepiece.

I am identical to the OP and use -1.5/-2.0 and they make a world of difference.

 

[dpt2014]

I have been down this road. All M diopters are the same! M3 to the 240, I have moved them freely between all M's. There is no modification -they simply thread into the existing eyepiece.

I am identical to the OP and use -1.5/-2.0 and they make a world of difference.

This is great news! I will be ordering mine from B&H this week!

 

[peterm1]

I have been down this road. All M diopters are the same! M3 to the 240, I have moved them freely between all M's. There is no modification -they simply thread into the existing eyepiece.

I am identical to the OP and use -1.5/-2.0 and they make a world of difference.

That is certainly my understanding although I have not tried it (moving the ssame diopter correcion lens from one to another camera) .

I did however buy a correction lens from a Japanses source for my M8. The M8 has a finder which does not give such a good view as the M9 and my old eyes needed help. This particular lens is actually designed to be an eyepiece magnifier which is how its advertised and sold. But in addition it has a diopter adjustment that is infinitely adjustable between plus and minus 3 by turning the rear part of the eyepiece. I think it cost close to $200. Which while not cheap is half the price of the equivalent Leica eyepiece enlarger (which also does not have inbuilt diopter adjustment). I went down this path mainly because I felt it gave better flexibility over time so if my eyeglass formula changes I can compensate quite easily.

This issue of eyepiece diopters comes up relatively regularly on sites like this as its something that confuses everyone. My post below explains a practical way of working out which correction you need for M cameras. Unfortunately I did not realsie that this does seem to not work for Bronicas since you actually have to replace the current eyepiece with the new one in that camera. Unlike the Leica system where the existing eyepiece stays in place and the diopter adjustment lens is added on top of or in line with it. (Thereby working just like a pair of reading glasses).

 

[dpt2014]

The magnification of -2 would be right but these are designed for the newer Ms (M6 and newer) They screw in. I'm not sure how you'd get one onto an M3.

Maybe a camera tech could modify your M3 with some newer M6 parts so you could use one. The diopter wouldn't replace he eye piece. It simply covers it.

I just received an e-mail from Leica USA that the current available diopters will fit ALL M bodies without modification.

 

[dpt2014]

What Japanese source did you purchase your adjustable diopter from?

That is certainly my understanding although I have not tried it (moving the ssame diopter correcion lens from one to another camera) .

I did however buy a correction lens from a Japanses source for my M8. The M8 has a finder which does not give such a good view as the M9 and my old eyes needed help. This particular lens is actually designed to be an eyepiece magnifier which is how its advertised and sold. But in addition it has a diopter adjustment that is infinitely adjustable between plus and minus 3 by turning the rear part of the eyepiece. I think it cost close to $200. Which while not cheap is half the price of the equivalent Leica eyepiece enlarger (which also does not have inbuilt diopter adjustment). I went down this path mainly because I felt it gave better flexibility over time so if my eyeglass formula changes I can compensate quite easily.

This issue of eyepiece diopters comes up relatively regularly on sites like this as its something that confuses everyone. My post below explains a practical way of working out which correction you need for M cameras. Unfortunately I did not realsie that this does seem to not work for Bronicas since you actually have to replace the current eyepiece with the new one in that camera. Unlike the Leica system where the existing eyepiece stays in place and the diopter adjustment lens is added on top of or in line with it. (Thereby working just like a pair of reading glasses).

 

[john_s]

What Japanese source did you purchase your adjustable diopter from?

Possibly this from Japan Exposures, previously called megaperl (megaperls?)

http://www.japanexposures.com/shop/...d=110&osCsid=6327ac2bbb9d5ad97b7885841a30262f

I have one. It converts an M6 0.85 to almost exactly x1.00, with the usual compromise: better viewing of the smaller frame lines for longer focal lengths and seeing less of the wide one. In my case, since my eye's accommodation is close to zero, it is quite fantastic. Optically excellent, fine adjustment. I'm not entirely convinced of the claimed adjustment range but I don't know how to check it.

Addition: it is generally regarded that the patent restriction on the site is nonsense.