Suitable tall loop for Hasselblad waist finder or focusing screen alone.

eli griggs · Jul 25, 2023

I have a very bright fresnel type screen with etched and clear cross hairs I've started using with my camera but because there is no prism at the center, I want to be sure my focus is right on.

Can anyone share their experiences with loops for the Hasselblad structure and, possible recommendations?

Steven Lee · Jul 25, 2023

If precise focusing is your goal, nothing beats Hasselblad 42013 chimney finder. This is what I use for open aperture portraits where you need the front corner of the right eye to be in focus. It is lightweight despite its appearance, blocks 100% of stray light, offers the highest magification of all finders, and comes with built-in diopter adjustment so you can tune it to your vision perfectly. And the best part: it's the cheapest finder and easily available.

The catch? The camera becomes awkward to transport and move around with.

Alan9940 · Jul 25, 2023

I don't use a loupe or even the waist level finder with my Hasselblad, but Toyo made a nice focusing magnifer that would probably work. Wista, and others, also made something similar.

Saganich · Jul 25, 2023

A linen tester might fit in there nicely.

Sirius Glass · Jul 25, 2023

I do not use a loop. If I am having problems focusing, I move the focus back and forth quickly.

BrianShaw · Jul 25, 2023

LOUPE, not loop.

Not sure what Hasselblad you have, Eli, but mine has a very useful magnifier in the waist-lelve hood. That is a great focus aid... all that is really needed (for me). I've tried a loupe on the ground glass and not found it very easy except in the case of the camera on tripod with a stationary subject, like a still life. Wit the finder in place you definitely need a long loupe; I use an eTone 6x that can be found on ebay or Amazon. Tried a shorter loupe on the GG without the finder and really had little success due to stray light. Perhaps a darkcloth would have helped but at that point I would just use a large format camera and call it a day.

Arthurwg · Jul 25, 2023

Eli, which focusing screen are you using? The 42219 Acute-Matt D with grid and split image seems to help.

itsdoable · Jul 25, 2023

I'll point out that the specification of the Hasselblad finders show that the Waist Level finder has the highest magnification (~4.5), while the Chimney has less (2.5 ~ 3.3, depending on version), and the 45/90 degree prism finders have the least (mostly around 2.5 ~ 3).

The big advantage of the chimney finder is the the better optics (multiple elements as opposed to a single magnifier) and the adjustable diopter - being able to see the screen absolutely clearly is essential in getting well focused images (provided your screen is calibrated). The infinite adjustable eyepiece can make a difference, especially with older eyes.

Sirius Glass · Jul 25, 2023

BrianShaw said:
LOUPE, not loop.

Not sure what Hasselblad you have, Eli, but mine has a very useful magnifier in the waist-lelve hood. That is a great focus aid... all that is really needed (for me). I've tried a loupe on the ground glass and not found it very easy except in the case of the camera on tripod with a stationary subject, like a still life. Wit the finder in place you definitely need a long loupe; I use an eTone 6x that can be found on ebay or Amazon. Tried a shorter loupe on the GG without the finder and really had little success due to stray light. Perhaps a darkcloth would have helped but at that point I would just use a large format camera and call it a day.

I have had the same experience.

The 45° PME prism makes the image more than large enough to focus the lenses. Use a prism and add a corrective eye piece is needed.

Eff64 · Jul 25, 2023

I like the chimney finder idea, and agree that will solve it for you.

eli griggs · Jul 25, 2023

I may find the budget for a good chimney later on, but the question is, because this screen has no split prism, only a thin etched crosshair

I'm no sure if the nomenclature but it is a very bright screen.

I can no post pics from phone at the moment but the screen is a fresnel, at an angle, you see concentric machining and clear cross hairs.

There are no notches.

There are no markings.

I suppose this is a third party tool.

wiltw · Jul 25, 2023

Keep your eye out for a used Peterson 6x6 loupe. When available new, the eyepiece came with a clear skirt and a black skirt, and the black skirt would be ideal for use as the magnifier of a MF focus screen. There were a variety of rubber base pieces, like a 135 format cutout and a 6x6 frame cutout; and the 6x6 base rubber had an outer dimension of 61mm and and ID of about 53mm. Unfortunately these do not appear to be available new any longer; I bought mine over 30 years ago.

Here was one on the used market

핫셀용 Peterson 6x6 Viewing Lens - 세광카메라

changecamera.cafe24.com

reddesert · Jul 25, 2023

Is the focusing screen actually clear in the center, not a ground matte surface? There is a type of focusing screen that has a matte/fresnel surface over most of the screen, but a clear spot with a fiducial mark (usually a crosshairs) in the center. These exist for Nikons and I believe for Hasselblads (but I don't have a Hasselblad so don't have first hand experience), and I have one for a 4x5 camera. The point of these screens is to help focusing slow lenses, like telephotos, or microscopes or telescopes with very shallow DOF.

These screens can be extremely bright because there is no ground glass diffusing the image. However, there is no focusing aid at the center. You have to focus on the aerial image using the crosshairs as a fiducial - you focus your eyes on the crosshairs and the aerial image at the same time. If you move your head side to side a little, you will see no parallax shift between the crosshair and the aerial image when the image is correctly focused. It's an acquired skill although quite repeatable once you practice doing it.

If you use a magnifier or loupe with such a clear-spot screen, it is imperative that the magnifier be correctly focused on the surface of the focusing screen. Otherwise you can wind up focusing the aerial image at the point of focus of the loupe, offset from the screen. The magnifier in a WLF should be as usable as an add-on loupe for the purpose, but any of them will require practice.

Eff64 · Jul 26, 2023

eli griggs said:
I may find the budget for a good chimney later on, but the question is, because this screen has no split prism, only a thin etched crosshair

I'm no sure if the nomenclature but it is a very bright screen.

I can no post pics from phone at the moment but the screen is a fresnel, at an angle, you see concentric machining and clear cross hairs.

There are no notches.

There are no markings.

I suppose this is a third party tool.

Not trying to minimize your concerns. You have come upon a subject about which many people have had issues in the past. The original Hblad screens were known to be dark and difficult to use unless the light level was very bright. I won’t try to get into the whole history of it here, it is well documented if you spend some time doing your due diligence. The Acute Matte series of screens came later and so forth, and were much better.

To your specific question though, I had tried at one point to use a loupe with my Hasselblads and did not like it.
1-unless you get one that will cover the whole focus screen, you won’t be able to see the edges, only the center
2-you have to stay with a lower magnifcation. Too much will only amplify the texture of your screen, and make it harder to judge sharpness. 5x would be max, 3-4 maybe the sweet spot
3-the waist level finder is not that big at the top, so getting a loupe to fit through there is going to be tough. Mine did not fit, and I was going to have to remove the finder to get the loupe onto the focus screen. Not only was that process itself a problem, but once the finder was off now stray light was coming into the focus area as well. The term “one armed paper hanger” comes to mind.
4-A good split image screen is selling for $400-500 these days. They scratch easily. Putting something like like a loupe onto and off of that surface is going to damage it, hindering the sharpness thereafter
5-I have seen those chimney finders for $100 or less. I haven’t looked at them in detail, meaning I’m not sure the price of a nice quality one, but to get a good loupe isn’t free.

I still stand by my original answer to you, I just skipped all of the detail in this post and cut to the chase.

Good luck with your search. I ended up biting the bullet and buying split image screens for all of my bodies because I couldn’t focus reliably with the others.

BrianShaw · Jul 26, 2023

Would you pay $10 for a chimney finder?

Sirius Glass · Jul 26, 2023

eli griggs said:
I may find the budget for a good chimney later on, but the question is, because this screen has no split prism, only a thin etched crosshair

I'm no sure if the nomenclature but it is a very bright screen.

I can no post pics from phone at the moment but the screen is a fresnel, at an angle, you see concentric machining and clear cross hairs.

There are no notches.

There are no markings.

I suppose this is a third party tool.

You could change the screen for one with a split center however I found that when I started putting on lenses with smaller aperatures, that the split screen went dark. This is why I use the screen you have or something similar to it.

eli griggs · Jul 26, 2023

I have the original 500cm non accuview split screen, but it's cracked in a couple of places and often too dark.

Once again I have to poor mouth and say, a bright, split prism screen is generally too expensive to be considered.

What I have for 500cm "V" screens were part of the original gift of this system and I just need to use them, correctly, but I would like to know the correct nomenclature, for now.

Thank you to everyone for your suggestions, they are all interesting and I'll keep my eyes open for a chimney, within my means.

Godspeed the all.

eli griggs · Jul 26, 2023

BrianShaw said:
Would you pay $10 for a chimney finder?

Of course I would; are you offering one?

Pieter12 · Jul 26, 2023

I wouldn't use a loop. A square knot would be more secure.

itsdoable · Jul 26, 2023

eli griggs said:
I may find the budget for a good chimney later on, but the question is, because this screen has no split prism, only a thin etched crosshair

I'm no sure if the nomenclature but it is a very bright screen.

I can no post pics from phone at the moment but the screen is a fresnel, at an angle, you see concentric machining and clear cross hairs.

There are no notches.

There are no markings.

I suppose this is a third party tool.

I had a look in Richard Nordin's Hasselblad Compendium, and they did sell a clear glass screen with etched cross hairs for photo microscopy (ie: no mate surface, just a pure clear glass screen with a Fresnel underneath). The part number was 42200 for both the acute matte and pre-acute matte version - they were probably the same screen, the pre-acute matte had printed black lines and the acute matte era screen had etched lines.

I've never seen one of those screen. But I'll take it off your hands if you don't want it

eli griggs · Jul 26, 2023

Sirius Glass said:
You could change the screen for one with a split c lenses with smaller aperatures, that t

itsdoable said:
I had a look in Richard Nordin's Hasselblad Compendium, and they did sell a clear glass screen with etched cross hairs for photo microscopy (ie: no mate surface, just a pure clear glass screen with a Fresnel underneath). The part number was 42200 for both the acute matte and pre-acute matte version - they were probably the same screen, the pre-acute matte had printed black lines and the acute matte era screen had etched lines.

I've never seen one of those screen. But I'll take it off your hands if you don't want it

This screen is a fresnel.

Held up to a single point light, in this case, a cellphone lamp, it is clearly presenting iridescent colours and the fresnel machining shows the concentric circles across the backside, which appear somewhat mat, at an angle, but other than the clear etched crosshair s, the top viewing surface is clear and strong.

Because there are no notches or markings like the later acute screens, which also are iridescent, I believe this to be something other than a Hasselblad product.

Cheers

bdial · Jul 26, 2023

I have one of the clear screens, just looking through it, everything is in focus. I never got the hang of working with the reference mark and the aerial image. Hasselblad recommends it only for photography through a microscope.
But the brightness is amazing. It would probably work well for astro photography too, since there is no need to worry about focusing.
It sounds like Eli has the standard cross-hair screen, aside from getting a different screen with either the split prism or micro prism,a chimney finder is probably the most cost effective solution to make the most of the current screen.

Suitable tall loop for Hasselblad waist finder or focusing screen alone.

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