Tuesday, January 1, 2019

X-Pro 1 Issues-Eyepiece Correction

Dante Stella published an informative post on the X-Pro1 in May of 2012 concerning practical accessories one might purchase for his/her new X-Pro1. I consider it a must-read for any new or seasoned  X-Pro user who wears eyeglasses, as I do, as it addresses potentially complications to the recent DSLR converts. I've extracted the most salient text here.

1. Eyepiece correction.

There has been some discussion about the eyepiece correction on the X-Pro1. This camera is shipped at -2, which is one diopter stronger than most cameras. Unlike the X100, the X-Pro1 has no built-in adjustment. Compounding this is an overlay of information that is not in the same plane of focus as the subject. This is not specific to Fuji; on virtually any camera with framelines, those are not in the same plane of focus as the subject. Your RF spot is in the same apparent focus plane because it - like the viewfinder - is a look-through exercise.

Neither the X-Pro1 nor the X100 will be fun for older people whose eyes don't focus as quickly or flexibly anymore. If you are young, you claim to bathe your precious bits in icy water, and your photographic life is dominated by nude pictures of your 25-year-old girlfriend, this viewfinder will not bother you a bit. In fact, by the time it* begins to hurt your eyes, the camera will be in a landfill. For everyone else, yes, your eye is going to do some focusing and refocusing in OVF mode. No diopter applied to the back side of the finder assembly is really going to solve the imbalance (one attached to the front would...), but you can mitigate things by picking a compromise correction lens that makes things a little easier at near and far.

* Camera's viewfinder? Her creeping tattoo habit? Hard to say.

The easiest solution may not be to search high and low for Cosina diopters - the X-Pro1 uses exactly the same 19mm thread that the Nikon F (round), F2, F3 (DE2, not high eyepoint), F3AF, FM, FM2, FE, FE2, FM3a, and FA use.
  • The FMx/FEx/FA eyepiece (thin rubber ring) is exactly what the X-Pro1 ships with. The same eyepiece shipped on the GS645, GS645s, GS645W, GA645, GA645w, and the -i versions of these cameras, as well as the GF670/Bessa III. Not surprisingly, these also show up on the Bessa R series cameras and the Epson RD-1 and 1s.
  • Outside of the Nikon world, this thin-rubber-ring eyepiece is available with correction ($20-30 for the Cosina version). There are a few examples floating around with Nikon labels, but they oddly lack the rubber part.
  • Nikon 19mm diopters for the F, F2 and F3 have a wider metal ring (they are actually in the same rings as the Nikon F2 and F3 standard eyepieces). If you keep your eyes open on Ebay or at KEH, you can find these eyepieces in -5 to +3 (and also in +0.5). You absolutely need to protect your plastic eyeglasses or sunglasses from this metal ring. It has serrated edges and will tear things up.
  • The F2, F3 and F3AF 19mm eyepiece is like the diopter, though with no correction and a fat rubber ring around it. This will still fit on the X-Pro1 (the rubber will rest on the black frame of the screen. But the rubber rings have a tendency of coming off, they push your eye away from the camera, and they tend to cut off the very corners of the finder. Sometimes it is worth buying one of these to get the rubber ring, which you can then transfer to the diopter. I would use rubber cement to glue it to the ring. Fuji used this kind of eyepiece (though without the rubber) on the GL690 and GM670.
  • The nuclear solution is the Nikon DG-2 magnifier, which has infinitely variable dioptric correction and is guaranteed to show only the central section of the finder (possibly but not likely usable for the 60mm Fujinon...).
Unlike Cosina diopters, which are labeled relative to the native correction of the eyepiece (i.e., a +1 is a +1), Nikon diopters are a touch more tricky. If you think you need a plus, pull out your cheapo closeup set (+1, +2 and +4) and use them sequentially over the rear eyepiece and see which one makes the OVF overlay look best. THEN subtract one from that number. That gives you the Nikon eyepiece correction. Nikon correctors show the resulting correction on a system with a native -1 correction. In other words,
  • A "zero" eyepiece (marked "0") is really +1
  • A +1 is really a +2
  • A +2 is really a +3
  • And likewise, a "-2" is really a -1, a "-3" is a -2, etc.
It is a little harder to choose nearsighted diopters, since no one has a bunch of labeled negative-powered lenses sitting around the house. Think about your prescription and then ask your eye doctor whether, given your astigmatism, you would increase the negative power or reduce it if you could only have a spherical correction (you don't get astigmatism corrections in camera diopters, sorry!). Be sure to point out that the viewing distance is near. Something an optometrist pointed out to me is that as you go negative, if things are getting sharper, keep going. If they start to look smaller, then you are past the point at which extra correction helps. So if you are choosing by trial and error with several eyepieces at once, this might be a way to attack it (and at least have a better chance of getting it right). Always check the OVF overlay and the EVF!

I found this posting particularly helpful when relying on the Optical View Finder (OVF) because the exposure setting readouts at the lower edge of the frame slip in and out of focus depending on the exact orientation of my progressive bifocals.  However, the actual subjects are seriously out of focus. This is because the eye is trying to simultaneously focus on a close subject (the exposure readout) and a distant one (the actual subjects). As blogger Stella points out, no amount of eyepiece correction will solve this problem.

Click here for photo source
David Hobby (a.k.a. The Strobist) actually spoke with the engineers who designed the X-Pro2, and he asked why a diopter eyepiece adjustment hadn't been included in the X-Pro2. While you can read his full posting here, here is the quintessential explanation.

The viewfinder is tight with glasses. Yes, it has a variable diopter (dial-in kind) and that in itself is a big progression from the X-Pro 1. Usable with glasses, yes. But a tight squeeze. And worse, in Tokyo I saw on public display the (rejected) prototype X-Pro 2 that included a physical lens-dialing diotper that would have given me sharpness and eye relief. 

I crumpled into a ball on the floor. (Why...)

We strongly considered it, explained a nearby engineer. But it was too easy to change the (physical lens-dialing) diopter inadvertantly as you pulled the camera out of your bag. So we went internal.

Oh. (sniffle... snot...) Okay. 

So, a miss for me—and a caveat for you, if you wear glasses. But I understand. Mostly.

Okay. A little bit of snark, but a whole lot of fact.