Are any of you using diopters for the Mamiya RB67 waist lever viewfinder? Do you have spare ones?

L Gebhardt said:

It's hard to tell using round batteries with a lot of space between them, but your camera seems fine. If it's hard to focus with the installed diopter try removing the finder and use your large format loupe to see how it compares. You might be able to just drop it into the finder if it's a long one.

Or just shoot with the 150 soft focus lens all the time and you'll never worry about getting sharp focus at all

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I normally use a 5x loupe on large format. When I focus through this 5x loupe on a large format focusing screen I see an obvious sharp point. For some reason I don't see as obvious a sharp point on the RB67. It's not any better.

The 150 soft focus gets sharp past F8 but only if you can reliably hit your mark. I do far better with batteries than people! I need to figure out how to be as consistent in the real world or I'll get rid of the system.

I will try @wiltw's flat plane test soon. Probably this weekend.

Certain Exposures said:

You know what they said about best-laid plans of mice and men...

Here's a link to scans from the focusing test. I haven't made time to read all your latest replies yet but I will. I will follow up with you all early this week.

Please let me know what you think based on these results:

Mamiya RB67 Pro-S Focusing Test

(http://imgur.com/a/0NXaFgV)

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They all look out of focus to me. The one in post #46 seems better.

Alan Edward Klein said:

They all look out of focus to me. The one in post #46 seems better.

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Did you click the link and look at all the lenses or did you only look at image #1 that appears as a thumbnail in post #48? There are 6 images total.

Certain Exposures said:

Did you click the link and look at all the lenses or did you only look at image #1 that appears as a thumbnail in post #48? There are 6 images total.

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I didn't notice that. Yeah, the next to the last seems the best for the focus on the middle battery.

Certain Exposures said:

I normally use a 5x loupe on large format. When I focus through this 5x loupe on a large format focusing screen I see an obvious sharp point. For some reason I don't see as obvious a sharp point on the RB67. It's not any better.

The 150 soft focus gets sharp past F8 but only if you can reliably hit your mark. I do far better with batteries than people! I need to figure out how to be as consistent in the real world or I'll get rid of the system.

I will try @wiltw's flat plane test this weekend.

Click to expand...

I agree you need to make the setup work in the real world. The test you've done and the better flat plane test will only ensure that the focus screen is the same distance as the film from the lens. But if it's off I don't think it's much.

You can focus with the lens stopped down on the RZ, and I assume the RB. In bright light that may help the SF lens.

Which focus screen to you have in the RB? The one in my current RZ is a Type A, which is a center spot that is just ground glass/matte plastic surrounded by a fresnel lens that helps keep the corners brighter. The center matte area is much easier to focus with than the fresnel surface. I've found this is also true on my large format cameras - I'm much more confident with a plain ground glass than the bright screens that use Fresnels or with an add on Fresnel behind the lens. Maybe a Type B, C, or E would help assuming the focus point is near the center. https://ianbfoto.com/downloads/Mamiya RB67/Mamiya RB67 ProSD Focusing Screens.pdf

Sorry if it's been asked, have you tried a different screen? I have not taken them apart yet, but I believe they are two-part compositions which means, especially if there are any marks suggesting tinkering, it was not put together correctly.

The screen I had trouble with, gave me not so much out of focus image, but sharp lines were rendered as doubles. I had only switched screen to fix that, but never looked at why it was doing that.

to Certain Exposures:

Just a question to see if my situation is similar to yours. If you wear glasses, are they for close up viewing or seeing things in the distance. Using my old eyes, I need +diopter reading glasses to read and see things close up. When using my TLR, I need extra + diopters. I initially just got a extra pair of reading glasses but they were +3.5 rather than my normal +2. It worked well except it was a pain to keep track of them as I needed to take them off in order to see the rest of the world around me. My final solution was very similar to Maris's suggestion but since I do not have the skill to cut down and round plastic glasses lens, I found a set of 2 stick on +2 diopter correction lenses from Amazon. They were meant to make bi-focals from a normal pair of glasses. I cut down the plastic lens, and with careful placement (they did not fully cover my magnifier pop-up), to get nice sharp negs from the camera. It took a bit to get use to it, but it works fine for me. Hope this helps a bit. Cheers!

Certain Exposures said:

Thanks, what do you mean in the sentence I bolded? Do you mean that I should measure the gap between the front of the Nikon lens and the top of the diopter I focused through on the RB67? Or do you mean I should measure the distance between the Nikon lens and the object itself in the real world?

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Hi, do the second way - measure distance between the Nikon lens and the real-world object.

Let me clarify what this does. When using the flip-up magnifier to focus it creates a "virtual image" for your eye to look at. This "virtual image" APPEARS to be at some specific distance from your eye; it depends on the strength of the magnifier AND its true physical distance from the ground glass. But there is no direct way to measure this "virtual distance." So what I suggest is to let the Nikon camera be focused, through the magnifier, on the "virtual image." In essence the Nikon camera/lens now "knows" how far away the "virtual image" is. So if you can transfer this Nikon lens focus point to the real world then you can physically measure (with a tape measure, etc.) the real distance. The "virtual image" is at the same "virtual distance" as the real-world distance which you physically measure.

So now that you know what the "virtual distance" is you can decide if you (your eye) can easily focus on something at that same real-world distance. If not, this will explain why it's difficult for you to be confident with your RB67 focus.

Certain Exposures said:

Here's a link to scans from the focusing test. I haven't made time to read all your latest replies yet but I will. I will follow up with you all early this week.

Please let me know what you think based on these results:

Mamiya RB67 Pro-S Focusing Test

(http://imgur.com/a/0NXaFgV)

Click to expand...

Looks like you hit focus reasonably well on all of them.

The 90mm @ F3.8 images are better for judging focus accuracy, as you can see the focal plane on the stool - I usually use a textured surface (like concrete) with an object on it, and you can then see the focal plane on the concrete to they edge of the FoV, which tells you if you are front or back focued, or if there is field curvature.

Since these appear to be OK, I'd say your camera is nominally in good shape.

Those questioning the focus accuracy of their cameras, AND the clarity of their own vision shoEuld begin by setting up focus target using planar surfaces, and an inclined plane to evaluate plane of best focus, then

1. Set their camera distance as measyured with a measuring tape between the plane of focus and the focal plane indiator mark engraved on the camera
2. Set the lens focus distance on the exact distance measured with measuring tape (step 1)
3. Evaluate the ability of their eye to focus on the focus screen texture (NOT on the image projected onto the screen)...and pick a diopter to adjust their reading distance vision to 1) best perceive the surface texture AND 2) having a sharp image projected onto the

If the screen texture is nicely visible to your eye, but the image projected onto the focus screen is not sharp, one can suspect that the mirror agle and/or focus screen position is NOT properly positioned so that the actual focus distance (determined by tape and set manually on the focus distance) is matching the reflex image on the focus screen.

I don't use diopters on my RB67 eyelevel viewfinder or any other camera but have progressive eyeglass lenses. How does that affect this whole subject?

Hello everyone, I haven't abandoned this project. I have a quick question before I reply to the remaining comments and share more observations. One side of the RB67 Pro-S focusing screen holder has "MAMIYA" stamped on it in white text.

Should that text face the film back or the lens? Does it matter?

Certain Exposures said:

Hello everyone, I haven't abandoned this project. I have a quick question before I reply to the remaining comments and share more observations. One side of the RB67 Pro-S focusing screen holder has "MAMIYA" stamped on it in white text.

Should that text face the film back or the lens? Does it matter?

View attachment 351160

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Does not matter.

Hassasin said:

Does not matter.

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Thank you!

Update:

Let's give this another couple weeks. I have a lot going on at the moment but I have not abandoned this project or thread. I will reply and share new info when it's ready.

Update:

I made a few new observations recently but nothing major to share with you yet. I still need to make time for several tests and to reply to everyone here. I'll be back. It might take a few more weeks.

I finally resolved an issue with a lens in a previous thread so believe me when I say I will return.

Certain Exposures said:

It's interesting that his site says the MP (micro prism) is better for portraits than the MPD (split screen).

I mainly need better focus for portraits.

Have any of you tried both?

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Microprism can be a very fast and accurate focus aid. Good light is when microprism is at its best. For portraiture I prefer it. Split image is a useful crutch in other situations, though.

BrianShaw said:

Microprism can be a very fast and accurate focus aid. Good light is when microprism is at its best. For portraiture I prefer it. Split image is a useful crutch in other situations, though.

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Thank you!

Again, I have not abandoned this thread. I will follow up. Most likely I will do that before the end of the year.

Happy New Year!

Certain Exposures said:

Thank you!

Again, I have not abandoned this thread. I will follow up. Most likely I will do that before the end of the year.

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Famous last words. No, I have not abandoned our thread. This began to get expensive for my time, my wallet, and my patience so I slowed down. Plus the holidays came up. I'll make a meaningful update at some point. There are still things I am working on.

I had another major development today. However, I have to wait a week and then do more tests before commenting on it. Stay tuned.

Certain Exposures said:

It's interesting that his site says the MP (micro prism) is better for portraits than the MPD (split screen).

I mainly need better focus for portraits.

Have any of you tried both?

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Yes, it would be nice if the image popped into focus without a split screen, but I find the split image works best for focus in all instances.

Arthurwg said:

Yes, it would be nice if the image popped into focus without a split screen, but I find the split image works best for focus in all instances.

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Okay, thank you.

L Gebhardt said:

I think it's important to know for sure that your camera is setup correctly. So I would do every thing possible to ensure you are sure of the focus. So bright light, take as much time as you need to trust you got it, mirror lockup, and a flat subject like a detailed paper or a ruler with fine markings and no gaps bigger than what you are willing to tolerate missing focus by (in other words not the batteries). A bright monitor might at an angle with a grid/pattern and focal point might be an easy subject. You can probably do the test for just your longer lenses but the shorter ones will allow you to focus closer so it will be good test to do them all.

Once those shots are done I'd also do your more realistic tests. Try one in dim light but still with the camera on tripod with mirror lockup. One in bright light but without mirror lockup. One focused fast on a real subject like a model's eye. Plan it out so you only waste one roll of film. If you need to I'd cut the number of lenses you test down to the fastest and the slowest ones since if it's the camera the issue should be the same across all the lenses but more visible at closer distances.

edit: I don't shoot a lot of people with film anymore, but you should definitely be getting sharp eyes at f/8.

also see https://petapixel.com/2013/03/12/gh...tion-tool-for-micro-adjustment-enabled-dslrs/, https://www.bobatkins.com/photography/technical/focus_testing.html and https://www.pointsinfocus.com/learning/diy/diy-autofocus-calibration-target/ for some ideas on making a focus testing target.

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wiltw said:

Rather than a series of cylindrical targets placed along an inclined plane, I would suggest FLAT front surface objects with which there is ZERO ambiguity about the plane of focus... like a series of paperback books, or VCR tapes that you may have, arranged like this example...

In this example, the focus plane was located on the center VCR box, and the inclined plane (ruler) should have had best focus at the 14" location on the ruler...if the actual focus plane were located in front or behind the plane of the center VCR box, it would be detected to be in 'best focus' somewhere else along the ruler.
Canon instructions for AutoFocus testing and microfocus adjustment of its AF dSLRs explicitly instructed to target FLAT PLANE focus targets. Canon also recommended that focus distance be 50 * FL for checking focus calibration.

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I did a new test last night based on these instructions. I will develop the film in a couple of weeks and report back.

(http://imgur.com/a/eOo4FLV)

Certain Exposures said:

I did a new test last night based on these instructions. I will develop the film in a couple of weeks and report back.

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I developed the film last night. Please let me know what you think of this focusing test shot and my comments below when you have a moment.

Observations

Summary: I can accurately focus on text on a flat plane with a significant amount of ambient light, mirror lock-up, and patience, but I still fail to achieve focus when working with live subjects. I cannot see when the subject's eye or face is in focus on the WLVF. I found it easier to judge the focus on the text on a book spine 7ft away through the WLFV than a human eye on a subject 4ft away.

Eye Exam

I put these tests on hold for a while because I needed an updated eye exam to rule out vision issues. I had a slight update. My vision is technically perfect again. However, it is not any easier for me to nail focus.


Repeat focusing test - no film.

First, I did a repeat focusing test with the 90mm lens I have because that's the focal length I plan to use most often.

I focused on the text on a book spine 4 feet away. I marked the side of the focusing rail with tape and a pen mark. Then, I focused back and forth several times in a row. I went back to the same mark every time.

So, my focus with the 90mm is consistent yet often inaccurate. I have not repeated this test for my other lenses yet. I think that is unnecessary based on the negatives from my film test.


Film Test - Focusing on book spines

I tested each of my lenses by placing my camera on a tripod just outside the published minimum focus distance of the lens, using mirror lock-up and a shutter release cable, and focusing on the words Artistic Anatomy on the spine of the Richer Hale book. Here's a view of the setup through my RB67's focusing loupe:

(http://imgur.com/a/eOo4FLV)
I exposed each frame at the widest aperture of the lens. I found it too hard to do the test indoors with ambient lighting from bulbs, so I used a powerful flashlight to illuminate the book spine just before taking each shot.

The shots are in focus under a 4x loupe on my light table. The sharpest point of focus should be at 5.5 inches on the ruler. However, it looks like things are just a hair sharper at 12. The text that says "End of the Line" on the John Free book looks just a little sharper to my eye. It could be an illusion because of the contrast on the spine of the John Free book. The two books should have been about the same distance from the camera.

All the book shots are sharper than any portrait I've taken until now. I would be happy if I could get my portraits this sharp.

Here's one of the book shots. I used the 250mm KL at F4.5 with 1 second of exposure, mirror lock-up, and 7.5ft away from the subject. The text Artistic Anatomy should be clearest. You need to open the full view in Imgur by clicking here instead of looking at the thumbnail below:

(http://imgur.com/a/T5eYMAf)
I should be able to get better scans of the whole roll in a couple of weeks.

Portraits

I took two more portraits in bright, mid-day window light indoors with a tripod and mirror lock-up. I missed focus on both of them.

I had a tough time getting the subject's eye in focus on the WLVF. There was no "pop" into focus. In one portrait, the focus is slightly in front of the subject. In the other, it's behind the subject. Neither shot is as sharp as the book shots.

I did some more research and thinking. I decided I will look for a Cds Chimney Finder because it has an adjustable diopter.

Please let me know if any of you have one that:

a) has clean glass
b) a functioning adjustable diopter
c) a functioning meter