What's new
Medium Format Forum

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.

The "best" prism for CWD?

C

christian_r

Member
Hi

I'm starting a new thread about prisms for CWD.

Which is the brightest prism for the cwd? I don't have a need for metering or hotshoe.
Are there different magnification amongst the prisms? Preferable one that will capture as much as possible of the cropped capture area.

Any experiences?

Is there any covering for the cropped area to buy?

Btw, the CFV back is just mind blowing, details, DR, colors.
 
Christian

All viewfinders can be used . But in my opinion , the best solution for the CFV back usage is the 4x4DPS viewer (3072534) . It has a very good magnification with a factor of 5,5 and the viewing area covers the 4X4 of the CFV screen .
Unfortunately , this viewer is out of production , but can occasionally be found in internet shops . That is , where I got mine , new ! ! !

Jürgen
 
I have a WLF, the 72754 hood, and PME-45 prism. The PME is used the most. For me, the TTL metering with the PME-45 was especially useful shooting film...the 12 exp/roll and waiting weeks for "feed-back" was a PIA for me; a hobbyist. With the digital back, I think that is less of problem. It comes down to cost. A good used PM-45 will run around $400-$600...a PME-45 $1200-$1400.

For me, with aging eyes, the down-side of the prism is the low magnification. That is the strong point of Jurgen's hood. I have just ordered a "flip-away" magnifier for my PME...hopefully that will help.

Steve
 
I was wondering, in relation to viewfinders, if people prefer using the Waistlevel Finder to a 45° prism finder (not taking into account the metering advantage). I find a WLF finder a real challenge for someone used to 35mm SLR photography; it is not to easy to obtain flat horizontal lines in landscapes, for instance. Also the fact that left and right are inversed, takes getting used to. I was wondering how many WLF users have actually switched to a 45° prism finder and if they find it easier to work with or not.
 
pascal said:
I was wondering, in relation to viewfinders, if people prefer using the Waistlevel Finder to a 45° prism finder (not taking into account the metering advantage). I find a WLF finder a real challenge for someone used to 35mm SLR photography; it is not to easy to obtain flat horizontal lines in landscapes, for instance. Also the fact that left and right are inversed, takes getting used to. I was wondering how many WLF users have actually switched to a 45° prism finder and if they find it easier to work with or not.
Click to expand...

The 45 is a lot easier..And for me at least, the eye cup adds a third point of stability when shooting hand-held.

Steve
 
It depends on the use.

With a CFV back all 90° finders are out. They will not fit as the back obstructs the finder.
For those who insist on 90° only the older finder designed for the 70 film back will do.

That leaves 0° chimney finders and 45° prisms

From the 45° prisms the PM 45 is most useful. It has an excellent adjustable
continuous dioptre setting. Magnification is modest, 2.5 times.
With extra lenses the dioptre range can even be expanded.

The prisms and the chimney finders have the advantage that they function well in areas
with high light levels.
A waist level finder will not be very useful in those circumstances.

For exact focusing the high magnification factor of the 4x4 DPS is very desirable.
Many DPS finders were not assembled correctly which leads to a non functioning dioptre
adjustment.
With careful refitting this can problem be solved.
 
The PM(E) is the one to go for if you are thinking of a 45° prism.

All Acute Matte screens have the same brightness.
The later "D" screens will be easier to use at very bright subjects.
 
christian_r said:
So the PM 45 is the one to go for?

I'm gonna change the acute matte as well, which one is the brightest?
Click to expand...

The best screen is the one that comes with the CFV back. It has the taking area etched, and is a later bright version.

Of the 45 degree metered prisms, I personally like the older one with the analog "ASA" and Max. Aperture dial verses the newer push button electronic one ... it's easier to use quickly. I have both styles. They are both very accurate ... these meters agreed with my hand meter everytime until I no longer use the hand meter.
 
I have the PME-45 and like it but recently with aging eyes have been having trouble being certain of accurate focus. I have become much less tolerant of "slightly off" focus. Went back to WLF or Hood but both are a bit of a "pain" to use compared to the prism. From old treads, I took "fotografz's" advice a got a swing out magnifer..looks as if it will be very helpful but haven't had a chance to use it yet. (Non-stop rain from Gustav)

Steve
 
For critical focusing - and this might be of interest to you - the best rig I've ever set up on my V Hassy is to use the WLF in conjunction with a 4x Rodenstock loupe I used to use on a 4x5 camera. This Rodenstock fits perfectly inside the WLF, and no one short of a blind person would have issues focusing accurately. As you can imagine, the optical quality of the Rodenstock loupe is befitting of the Hasselblad. And if the image were any brighter, you'd need sunglasses!! But, of course, compromise takes over, as this rig is only useful for the same types of subject matter and conditions where you might use a large format camera. But man does it ever work! On a tripod, it can be very useful for head & shoulder shots too, or close macro shots. But only after you've got the compositional elements in check, as it really shines (no pun intended) when shooting wide open, where only a tiny portion of the image is to be critically sharp. Nothing that I know of beats this rig.
For most shooting, however, I prefer the PME 51 over the WLF, but the size and brightness of the image are both compromised. As mentioned, it is very accurate in normal lightling, but (I find it to be) predictably off in unusual lighting.
I've discovered too, that to get a decent amount of data on the right side of the CFV histogram (without clipping) I have to over expose about a stop. Thus, when I set the CFV to 50, I'll set the PME 51 to 25, and go from there.
Michael H. Cothran
 
Michael,

You have made me curious how the Rodenstock loupe looks like fitted to the WLF.

Could you post a picture of this set up?

I use a handheld meter and or spotmeter with my 503CW.
Other users have informed me they get excellent results even with low light levels using any of the PME series prisms.
These prisms are often praised for being acurate.
I am interested to know what unusual lighting conditions you mean where these prisms fail to give good readings.

How is the 250 lens doing?

Paul
 
The metering results of my PME45 , 203FE and my MINOLTA AUTOMETER IV
match with only about a 1/3 stop .

But as you say , using the CFV back , to get a reiable histogram , the sensitivity of the meter has to be set one complete stop lower .
When using ISO 200 in the back , I set the meter to ISO 100 .
Sometimes , even that is not sufficient .

Michael
You mentioned to send an image for the Calendar project . Go ahead , and please do .

Regards Jürgen
 
polypal said:
Michael,

You have made me curious how the Rodenstock loupe looks like fitted to the WLF.

Could you post a picture of this set up?

I use a handheld meter and or spotmeter with my 503CW.
Other users have informed me they get excellent results even with low light levels using any of the PME series prisms.
These prisms are often praised for being acurate.
I am interested to know what unusual lighting conditions you mean where these prisms fail to give good readings.

How is the 250 lens doing?

Paul
Click to expand...

Man, it's been a while since I used this rig, and I had it somewhat wrong. It does not fit inside the WLF as I stated, but inside the focusing screen area. The WLF has to come off. I don't know why I thought it was going inside the actual WLF - maybe wishful thinking? But, nonetheless, the Rodenstock loupe covers just the entire area of the screen, except for the corners of course, and is as bright and snappy as can be, even in sunlight. I'll try to take a picture of it this weekend. I think maybe I was thinking of my RZ67, which had a bigger WLF. As my son would say - "my bad."

As far as the PME 51 meter is concerned, it's a strong centered-weighted meter, stronger so than the old Nikons, but does not have the ability to "think" like a matrix or evaluative meter can. I find that any bright or dim lighted area, especially close to the center can adversely affect the reading. I will open up or close down a bit (educated guess) if there is a significant highlight or shadow area near the center. Just as with any center-weighted, spot, or average meter, one must be diligent in evaluating the light source(s) at hand before committing to the meter's recommendation. With film this was much more important, as it could cost you dearly if your exposures were wrong. With digital, it's no big deal, since you can test fire, see an instant histogram, and go from there.

As far as the 250 goes, I grabbed it Tuesday morning to take to Forrest Repair after work, flicked the DOF a couple of times, and...it worked. I fired it on the camera @ f5.6 and f45, and it worked fine. So, long story short, I didn't take it in. I haven't done anything with it until just now, after reading your post, so I got it out, flicked the DOF, and it's sticking again. It closes down, then it doesn't. So, I'll take it in Monday for sure now. I'm thinking that maybe since it works sometimes that the ring you spoke of is not broken. Could it just need lubrication? Forrest, btw, charges $125 labor for an overhaul.
Michael H. Cothran
 
Michael
You mentioned to send an image for the Calendar project . Go ahead , and please do .

Regards Jürgen[/QUOTE]

Actually, I had just inquired that you were still wanting images, as I thought you had enough. But when I asked, I had in mind a place down the road where there are some rundown old frame structures, and thought one of those might be fitting. I may venture there tomorrow, and if successful, I'd be honored to submit.
Michael
 
Michael,

Difficult to say what is the cause of the problem with your 250 lens with this new information.

Could even be just sticky blades that need cleaning.
The price for a full service sounds pretty good.
CF lenses are quite strong and do not need much attention.

That reminds me:
Storing lenses for longer periods of time is best done with the aperture selected and closed to the smallest opening (highest F number)

I can not explain why but this way the chance that aperture blades become sticky is practically nil.

The 250 is not a lens that will see much use.
Chances are the aperture just needs cleaning.

Paul
 
Thanks Paul. I agree whole-heartedly about storing lenses. I always close the lens down all the way when off the camera, but I can't remember exactly why. It started with some of the first Nikon lenses I owned. O well, if it comes to me, I'll post it, fwiw.
I thought $125 was decent, slightly cheaper than David Odess, but a lot cheaper if you factor in 2-way shipping.
I just played with the 250 again, and it closed down normally several times. Then it stuck. Could be that maybe the ring is slightly broken, so that sometimes it catches, and sometimes it doesn't. I note that when the blades do stop down, they do so instantly. I would think they would drag somewhat if they were dry.
And you're right, the 250 does not get a lot of use. Not nearly as much as I'd like. Even my 100 & 180 get out very seldom nowadays. I've always been a long lens fan, much more so than with wide angles, but the 40 CF FLE I bought a few months ago has seen almost 100% of my image taking since buying the CFV. Any shooting with another lens has been pretty much forced - just for the sake of justifying its existence in my case. I guess I'm seeing the world in a new perspective now.
Michael
 
About the storage of lenses, should just the aperture be stopped down, or should the DOF preview be switched on as well??
 
macmx said:
About the storage of lenses, should just the aperture be stopped down, or should the DOF preview be switched on as well??
Click to expand...

Yes, the DOF preview button should be engaged. Otherwise the aperture will remain open regardless of the f-stop set on the aperture ring. The same goes for when the lens is stored on camera with the shutter cocked.
Focal plane lenses, on the other hand, will automatically stop down when removed from the camera body. This is not the case with leaf shutter lenses like those used on the 500 series bodies.
But truth be told, I'm not sure how important it is to store lenses stopped down. Maybe I'm just a little bit left of eccentric for doing so!!
Michael H. Cothran
 
Just selecting the smallest aperture does not do it.
The lens must effectively be stopped down meaning the DOF lever must be used to close the aperture.



Michael,

Thanks for your explanation. To me it is not something eccentric but good advice given to me
by my technician. He demonstrated this good practise by showing lenses in his collection
that were not used for several years.
All these lenses behaved flawlessly at first command.
No delay or slow action of the aperture. All closed down as if they had been used yesterday.

Paul
 
You must log in or register to reply here.
Back
Top