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500C/M focusing issues

nameBrandon

Well-known member
I know there are some very well versed members out there in the 500/V-series world, and I was hoping to figure out here if the focusing challenges I"m experiencing are on me.. or on something I've perhaps not done not the camera properly.

The original focusing screen that came wih my 500C/M was super dark, so I replaced it with one from B&H ( https://www.bhphotovideo.com/c/prod...blad_3042264_focusing_screen_for_cfv_50c.html ) and that had modern 4:3 frame lines for the CFV ii 50c back.

I'm used to a Leica rangefinder and I understand how that should work.. it was my understanding that something similarly, visually, would be happening with this focusing screen but I can't figure it out.. I don't know if I have it wrong, or conceptually if I'm not understanding how this should work.

Firstly, what is the proper orientation for the focusing screen? Should the line in the circle be horizontal or vertical? Beyond that, what am I looking for as far as an in focus indicator? I see the circle but with the inter circle, usually the top half is dark or the bottom half is dark, and the outer circle never really looks any differently than the rest of the focusing screen.

Maybe my eyes are just too far gone at that distance to properly use this type of focusing screen? If anyone can point to a YouTube video or anything that might demonstrate what I *shoud* be seeing, I'd really appreciate it.

Thanks!
 

glennedens

Active member
Brandon, I'm sure you are doing this, however I'll proceed, if 1/2 of the split image is dark then that typically meant not enough light is getting to the screen - are you sure the lens is opened up all the way (max aperture)?

I had my split-image screen mounted so the split was horizontal, it might not work if the "split line" is vertically oriented. I vaguely remember some third party made a split-image screen with a diagonal "split image" and that was supposedly an achievement in the day (talking early 70's here).

With the split image you want to find a vertical line and match up the two halves of the split image, the outer part of the screen can serve as a typical ground glass if you've used a view camera (sounds like you have?) although I always found that harder - of course remember my comments on eyesight in the other thread :)

I found that if a lens was f5.6 or higher then the split image would not work as well, 1/2 or both halves would be dark, and for sure by f8 or f11.

And as was mentioned in another thread the alignment of the focusing screen to the body and the registration to the digital back are critical. This is rare, I once had a used 500CM that was so well worn that the rear registration plate (rear body plate) had to be replaced.

Hope this is helpful in some small way, Waiting for my 503CW to come back home from its long-term loan to a friend.

Glenn

I know there are some very well versed members out there in the 500/V-series world, and I was hoping to figure out here if the focusing challenges I"m experiencing are on me.. or on something I've perhaps not done not the camera properly.

The original focusing screen that came wih my 500C/M was super dark, so I replaced it with one from B&H ( https://www.bhphotovideo.com/c/prod...blad_3042264_focusing_screen_for_cfv_50c.html ) and that had modern 4:3 frame lines for the CFV ii 50c back.

I'm used to a Leica rangefinder and I understand how that should work.. it was my understanding that something similarly, visually, would be happening with this focusing screen but I can't figure it out.. I don't know if I have it wrong, or conceptually if I'm not understanding how this should work.

Firstly, what is the proper orientation for the focusing screen? Should the line in the circle be horizontal or vertical? Beyond that, what am I looking for as far as an in focus indicator? I see the circle but with the inter circle, usually the top half is dark or the bottom half is dark, and the outer circle never really looks any differently than the rest of the focusing screen.

Maybe my eyes are just too far gone at that distance to properly use this type of focusing screen? If anyone can point to a YouTube video or anything that might demonstrate what I *shoud* be seeing, I'd really appreciate it.

Thanks!
 

docholliday

Well-known member
Practically, you can orient the screen any direction to suit your needs. The split can be any of the 90deg orientations, depending on how you want the split to work. There's always been note for V shooters that the two Acute-Matte-D notches be placed in the upper-right corner of the screen (nearest to the winder knob/shutter release). But again, it doesn't matter. A lot of landscape shooters would set the split to vertical, so it was easier to see the focus line against a horizon. Portrait shooters would typically set it horizontal so that the nose, eye, or a hair was split for easier viewing. There were also 45deg split screens for a compromise.

Focusing was usually best when used with the WLF mag and one could really see the change. There were also split with microprism screens that made it more functional, but at a risk of creating a busy finder. Also, some of the PME prisms would go wacky with too many items in the middle. A bright lens was needed for best effect. On the 110/2 and 203FE, it was beautiful. But, with some of the 5.6 lenses, it would be really hard to use and sometimes required simply visual focusing.

To use, simply put the split line on anything that you wanted to focus, preferably with good contrast. Then, rotate the focus ring until the image was "whole". If out of focus one way or another, the two halves of the circle with show the image slid sideways from each other. With the microprism screens, you'd simply focus until the image "cleared" up without the microprism pattern.

I never used any of the "aids" on my screens. I preferred plain, clean Acute-Matte-D screens with an overlay of a grid and custom markings that I'd create using a color laser and transparency film (for overhead projectors). I also went to an optometrist friend to get a custom diopter plate made for my WLF and the focus would "snap" in as soon as it was in focus.
 

glennedens

Active member
Doc's description is far better than mine :).

Practically, you can orient the screen any direction to suit your needs. The split can be any of the 90deg orientations, depending on how you want the split to work. There's always been note for V shooters that the two Acute-Matte-D notches be placed in the upper-right corner of the screen (nearest to the winder knob/shutter release). But again, it doesn't matter. A lot of landscape shooters would set the split to vertical, so it was easier to see the focus line against a horizon. Portrait shooters would typically set it horizontal so that the nose, eye, or a hair was split for easier viewing. There were also 45deg split screens for a compromise.

Focusing was usually best when used with the WLF mag and one could really see the change. There were also split with microprism screens that made it more functional, but at a risk of creating a busy finder. Also, some of the PME prisms would go wacky with too many items in the middle. A bright lens was needed for best effect. On the 110/2 and 203FE, it was beautiful. But, with some of the 5.6 lenses, it would be really hard to use and sometimes required simply visual focusing.

To use, simply put the split line on anything that you wanted to focus, preferably with good contrast. Then, rotate the focus ring until the image was "whole". If out of focus one way or another, the two halves of the circle with show the image slid sideways from each other. With the microprism screens, you'd simply focus until the image "cleared" up without the microprism pattern.

I never used any of the "aids" on my screens. I preferred plain, clean Acute-Matte-D screens with an overlay of a grid and custom markings that I'd create using a color laser and transparency film (for overhead projectors). I also went to an optometrist friend to get a custom diopter plate made for my WLF and the focus would "snap" in as soon as it was in focus.
 

nameBrandon

Well-known member
Who is ready to laugh at Brandon?

.
.
.

I just found out about the magnifier. I didn't know it existed until I stumbled upon an old manual. I read about the magnifier, but I had just assumed that was the term for the whole focusing screen box..So yeah, now it works as expected. I had been trying to "eyeball" focus with the split prism screen at waist-level without the magnifier! I'm sure some young, bright-eyed 20-something can probably pull it off but my eyes have seen better day for sure..

Anyways, this is so, so much better with the magnifier.. :)
 

darr

Well-known member
I want to add my experience using my Hasselblad digital back CFV-50c and focusing with the Acute-Matte screen it came with, the same one OP refers to:

I have two bodies, a 501cm and a 503cx. The 501 I dedicate to film shooting and the 503 to digital, but I have the same focusing experiences with both bodies and the 50c.

Shortly after acquiring the 50c I bought the Hasselblad viewfinder magnifier #42459 after reading it could help nail focus when using the digital back as I was missing focus for the first time ever. Focusing using film had been part of my job and frankly it was one of the easier parts of shooting for me as I always nailed it, but now with the 50c I was having a focusing issue.

After numerous tests this is what I found. I could easily see the 2x magnified view of the split screen circle with my PM90 and #42459, but found I did not need the magnification for my vision (removed it after testing), but heck it was made for focusing issues so I did some testing with it. What I found using both bodies with the split screen focus nailed in the viewfinder was the images were out of focus on the live view screen! There is a critical difference in the focal plane between my 50c and the film backs I shoot with, no doubt about it.

How I focus with digital
I use two techniques depending if I am studio shooting or landscape shooting. In the studio after composing through the viewfinder, I then use live view to nail focus. Out in the landscape I use hyperfocal focusing and if I need to use live view for closer focusing, I generally use my Hoodman rubber loupe over the 50c screen. This has worked for me since acquiring the 50c in 2014. I always nail focus using f/16 with hyperfocal and I always nail focus using live view and no problems when shooting film the old fashion way. I also run tests on newly acquired lenses for hyperfocal shooting. I use the 50c in the same manner on my Alpa, Linhof and Cambo cameras with no issues.

Kind regards,
Darr
 

nameBrandon

Well-known member
Roger that.. :) It was a relatively stressful 90 minutes.. I've earned my "Lens Cocking Procedure" merit badge at this point, though..!

IMG_5661.jpg
 

sog1927

Member
I know there are some very well versed members out there in the 500/V-series world, and I was hoping to figure out here if the focusing challenges I"m experiencing are on me.. or on something I've perhaps not done not the camera properly.

The original focusing screen that came wih my 500C/M was super dark, so I replaced it with one from B&H ( https://www.bhphotovideo.com/c/prod...blad_3042264_focusing_screen_for_cfv_50c.html ) and that had modern 4:3 frame lines for the CFV ii 50c back.

I'm used to a Leica rangefinder and I understand how that should work.. it was my understanding that something similarly, visually, would be happening with this focusing screen but I can't figure it out.. I don't know if I have it wrong, or conceptually if I'm not understanding how this should work.

Firstly, what is the proper orientation for the focusing screen? Should the line in the circle be horizontal or vertical? Beyond that, what am I looking for as far as an in focus indicator? I see the circle but with the inter circle, usually the top half is dark or the bottom half is dark, and the outer circle never really looks any differently than the rest of the focusing screen.

Maybe my eyes are just too far gone at that distance to properly use this type of focusing screen? If anyone can point to a YouTube video or anything that might demonstrate what I *shoud* be seeing, I'd really appreciate it.

Thanks!
The orientation of the split-image isn't important. It'll work either way. Hasselblad made an Acute-Matte with a 45 degree split and a microprism at one point. I have those in both the 500 C/M and the 503CW. The only thing that's really orientation-sensitive on that screen are the markings for the CFV-50c. What you'll find is that the vertical orientation works best for subjects with horizontal lines/edges you can use for a focus target, and the horizontal works best for subjects with vertical lines. I always found the 45 degree split to be a nice compromise.

As for the circle being dark, what lens are you using? The circle will black out with slower/longer lenses or if your eye isn't aligned with the center of the screen (the longer the lens, the more sensitive this is to alignment). If you're lined up correctly, the image in the two halves of the circle will be displaced from one another when you're out of focus. They'll line up when the focus is correct (assuming your body is within spec). The microprism (outer ring) should "shimmer" when you're out of focus. If you're using the WLF, you may find the magnifier to be helpful. Diopters are available to correct for less-than-perfect vision.
The newer chimney finders are adjustable, and diopters are (or used to be) available for the prisms.

It's an acquired skill - you'll pick it up with practice.
 

sog1927

Member
The orientation of the split-image isn't important. It'll work either way. Hasselblad made an Acute-Matte with a 45 degree split and a microprism at one point. I have those in both the 500 C/M and the 503CW. The only thing that's really orientation-sensitive on that screen are the markings for the CFV-50c. What you'll find is that the vertical orientation works best for subjects with horizontal lines/edges you can use for a focus target, and the horizontal works best for subjects with vertical lines. I always found the 45 degree split to be a nice compromise.

As for the circle being dark, what lens are you using? The circle will black out with slower/longer lenses or if your eye isn't aligned with the center of the screen (the longer the lens, the more sensitive this is to alignment). If you're lined up correctly, the image in the two halves of the circle will be displaced from one another when you're out of focus. They'll line up when the focus is correct (assuming your body is within spec). The microprism (outer ring) should "shimmer" when you're out of focus. If you're using the WLF, you may find the magnifier to be helpful. Diopters are available to correct for less-than-perfect vision.
The newer chimney finders are adjustable, and diopters are (or used to be) available for the prisms.

It's an acquired skill - you'll pick it up with practice.
I forgot about the viewfinder magnifier for the prisms. I have one of those, too.
 

jng

Well-known member
I learned the hard way that focusing these old 500 series bodies on a digital back (in my case an IQ160) can be an epic journey down the rabbit hole. There's very little tolerance for error with high resolution sensors compared to film. I've used the waist-level finder (both older and newer versions), chimney finder, various prisms, prism with view magnifier, Acute Matte D w/split image and microprism collar, Acute Matte plain screen...

The newer waist-level finder (4.5x magnification vs the older one's 3x magnifiction) with plain Acute Matte screen worked best for me as it gave the best combination of magnification and brightness. I found the PME51 (3x) to be a bit dim. Adding a view magnifier (2x for total of 6x mag) helped but was kludgy as the view magnifier only covered the center ~third of the field of view. I thought the split/microprism screen would help me with my aging eyes but alas it was out of tolerance relative to my plain screen, which gave accurate and pretty reproducible focus in good light.

And of course the critical link in the chain is whether the focus path is properly aligned and calibrated. The mirror's alignment goes off with use (all that slapping around with each exposure) so needs regular checking and adjusting, and the (adjustable) height of the screen is also an important factor (no two screens are necessarily alike in this regard). Not to mention whether the body itself is square. These old Hasselblads can last forever but they do need regular servicing to keep them in spec. I'd say you're quite lucky if you happen to pick up a random body that's within spec and gives accurate focusing on one of the newer digital backs.

Not that I don't love my old Hasselblads or regret all the frustrations, learning and fulfillment I derived by using them on both film and digital. I have an old 500C that's been in my possession since the mid-70's and a more recently acquired 501CM that I'll pamper until it sees a 100 Mp back attached to it. :D Oh and my prized SWC...

John
 

Godfrey

Well-known member
I have a few screens. My most successful for focusing with the Planar 80 is the Hasselblad screen with split image at a diagonal split orientation. With any of them, the consistency of my focusing goes way up with I use the focusing magnifier chimney rather than a Waist Level finder with magnifier ... that's because the chimney allows me to focus the ocular precisely so I can see the focusing screen best where any of the WL finder magnifiers is just approximate.

Of course, if you're in need of the very best critical focus, use the back in Live View mode and focus on the LCD (presuming you're using the CFVII 50c). This requires you lock the lens and body shutter open for focusing.

The Acute Matte plain matte fresnel, preferably with horizontal and vertical scribe markings, is actually my favorite and particularly when using the 120 macro lens.

Oh yes: the split image black out can occur for one of several reasons:
  • The lens isn't fast enough for the split image prisms to image properly.
  • Your eye is not on the optical centerline for the split image prisms to work properly.
  • The particular split image prisms are not tuned for the focal length of the lens in use.
Any one or combination of these issues can result in a split image blackout. (Long telephoto lenses are the hardest to get good action with the split image aid in particular.)

G
 

pflower

Member
I had the original CFV 50 back on an old 503cx and found that well over 50% of my initial shots were not sharp. I had the camera serviced for focusing - the mirror can slip out of exact alignment and the back plate can become worn. After the service focusing through the WLF became much much more effective. I highly recommend a service by a Hasselblad specialist for the camera concentrating on focusing issues. Not particularly expensive and it can make a huge difference.



I want to add my experience using my Hasselblad digital back CFV-50c and focusing with the Acute-Matte screen it came with, the same one OP refers to:


After numerous tests this is what I found. I could easily see the 2x magnified view of the split screen circle with my PM90 and #42459, but found I did not need the magnification for my vision (removed it after testing), but heck it was made for focusing issues so I did some testing with it. What I found using both bodies with the split screen focus nailed in the viewfinder was the images were out of focus on the live view screen! There is a critical difference in the focal plane between my 50c and the film backs I shoot with, no doubt about it.

How I focus with digital
I use two techniques depending if I am studio shooting or landscape shooting. In the studio after composing through the viewfinder, I then use live view to nail focus. Out in the landscape I use hyperfocal focusing and if I need to use live view for closer focusing, I generally use my Hoodman rubber loupe over the 50c screen. This has worked for me since acquiring the 50c in 2014. I always nail focus using f/16 with hyperfocal and I always nail focus using live view and no problems when shooting film the old fashion way. I also run tests on newly acquired lenses for hyperfocal shooting. I use the 50c in the same manner on my Alpa, Linhof and Cambo cameras with no issues.

Kind regards,
Darr
 

Godfrey

Well-known member
I had the original CFV 50 back on an old 503cx and found that well over 50% of my initial shots were not sharp. I had the camera serviced for focusing - the mirror can slip out of exact alignment and the back plate can become worn. After the service focusing through the WLF became much much more effective. I highly recommend a service by a Hasselblad specialist for the camera concentrating on focusing issues. Not particularly expensive and it can make a huge difference.
I love reading "on an old 503cx" when I consider that both of my 500CM bodies are a decade older than the first of those (1979 and 1978). The 503cx first shipped in 1988. :)

I haven't had either 500CM serviced since I bought them, in 2013 and 2020 respectively. I have, however, tested the focusing calibration on both of them extensively with both A12 film and the CFVII 50c backs. As far as I can tell from examining the negatives with 8x and 15x loupes and comparing them to the digital capture, if they are off, they are both off by the same amount. And the magnifying hood with focusing ocular has the same influence on the consistency of my focusing with film as it does with the digital back ... it's just a heck of a lot easier to go to 100% magnification with the digital image and see how far off it is than it is with the digital image on a high resolution computer display!

I will probably have the bodies serviced over the next year as they are now back in operation and it's a good precaution. But my workaround to minimize the loss of focusing consistency (which I attribute to my crappy eyesight) is to just stop down one to two stops more than I would with the same lens and distance on the digital back ... That seems to cover my average focusing error well enough in most cases.

G
 

nameBrandon

Well-known member
I love reading "on an old 503cx" when I consider that both of my 500CM bodies are a decade older than the first of those (1979 and 1978). The 503cx first shipped in 1988. :)

I haven't had either 500CM serviced since I bought them, in 2013 and 2020 respectively. I have, however, tested the focusing calibration on both of them extensively with both A12 film and the CFVII 50c backs. As far as I can tell from examining the negatives with 8x and 15x loupes and comparing them to the digital capture, if they are off, they are both off by the same amount. And the magnifying hood with focusing ocular has the same influence on the consistency of my focusing with film as it does with the digital back ... it's just a heck of a lot easier to go to 100% magnification with the digital image and see how far off it is than it is with the digital image on a high resolution computer display!

I will probably have the bodies serviced over the next year as they are now back in operation and it's a good precaution. But my workaround to minimize the loss of focusing consistency (which I attribute to my crappy eyesight) is to just stop down one to two stops more than I would with the same lens and distance on the digital back ... That seems to cover my average focusing error well enough in most cases.

G

Let me know when you send yours in, maybe we can get a group discount.. :p
 

nameBrandon

Well-known member
LOL! I don't know whether Dave Odess can afford to provide group discounts... :) He's who I usually send my Hasselblad V system gear to for servicing.

G
Does he need the back with the camera to do focusing alignment? That's probably a dumb question.. I just don't think I could be without the back for multiple weeks.
 
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