Trying out CFV50c, lens questions...

[ondebanks]

Getting back to the Planar 120, I am pretty sure that field curvature is at play, here are the MTF-curves at infinity:

Interesting! That big dip in the middle of the infinity plots definitely looks like field curvature alright.

Here are the same plots for the Mamiya 12/4 macro N:

In their primary macro regime, the Mamiya [at 1:1] is fairly similar to the Hasselblad [at a less closeup 1:1.5].
But there is a world of difference at infinity!

I scanned these charts from a 1997 MAC brochure, which says of the 120/4 macro: "It is a state-of-the-art, modified Gauss design with an adjustable floating group for variable flat filed correction, using Mamiya's own formulation of high density/low and ultra-low dispersion glass".

Ray

 

[Kabraxis]

Pascal, what a vast test! Did you use CA-reduction on these?

No correction for CA applied while development. You may download the RAW file to check by yourself.
Regards
Pascal

 

[Udo]

Question on the aspect of setting the exposure time on the back it self. It would appear to be a default of 1/8th of a second, so:

1. Do I have to change that value every time I change the shutter speed?

2. If not the above, is there any harm in setting it at somewhere between 1-30 seconds so I can use those speeds at will?

1. You have to change the setting only if your exposure time is going to be longer/slower than the default time (1/8th).
2. The sensor will be active and ready to capture photons for the period of time you have set, even if the lens shutter is already closed. So it is likely that the noise floor/level will be raised.

Regards, Udo

 

[ErikKaffehr]

Ray,

Thanks for filling in.

I have seen some info from Zeiss, in part from Hubert Nasse's articles and indirectly trough "Diglloyd's" writing that floating elements are needed to allow planar field at different focusing distances. As you noted the Mamya macro has floating elements.

Now, older macro lenses often were of traditional double Gauss design. Interestingly, Zeiss developed a new Macro for the Contax 645, called the APO Planar 120/4 which is quite different from the Hasselblad lens. The Apo Planar has an extra group of two elements, which I presume is a field flattener and it has variable air space.

That lens is very good at infinity and also at 1:1.

Just to mention, right now I am waiting for a Sony 90/2.8 macro that will be shipped with the Sony A7rII I am waiting for, that lens has 15 elements in 11 groups and variable air space. The corresponding Nikon and Canon macros are of similar complexity.

So, very obviously, modern designs are much more complex than older ones.

Best regards
Erik

Interesting! That big dip in the middle of the infinity plots definitely looks like field curvature alright.

Here are the same plots for the Mamiya 12/4 macro N:

In their primary macro regime, the Mamiya [at 1:1] is fairly similar to the Hasselblad [at a less closeup 1:1.5].
But there is a world of difference at infinity!

I scanned these charts from a 1997 MAC brochure, which says of the 120/4 macro: "It is a state-of-the-art, modified Gauss design with an adjustable floating group for variable flat filed correction, using Mamiya's own formulation of high density/low and ultra-low dispersion glass".

Ray

 

[darr]

Well darn...

I just got the Hassy PM90 prism and it is out of focus something serious. I got it from KEH and it looks virtually brand new, has the standard neutral diopter ( OD/90 ). I tried it on three bodies, my wife looked through it ( I now use a -1.5 ) and it is completely back focused meaning the point is behind the surface of the prism that faces the screen. I took the diopter off and in no way did that help, part of the optical path although all I saw was the back of the prism, no optics.

Besides the obvious of returning it hassle free to KEH, any suggestions on trouble shooting this? In looking at the photos, does this look right or is it missing something?

It looks identical to my PM90, diopter and all. The only thing I would suggest, but you probably already checked it out, is to make sure the focusing screen is installed correctly in your camera body. I have installed the focusing screen that came with the CFV-50c back in my 501CM and it works well. KEH is real good about returns. I have been dealing with them since you could walk-in off 14th Street in Atlanta and go through their bins. When they moved to Smyrna in the 90s, they stopped being a retail store and became strictly mail order, but their return policy has always been the best in the business IMO.

What lens were you testing the PM90 with?

Kind regards,
Darr

 

[jlm]

my P90 has the two blue lines on it (it has the cutaway for the light meter dissplay for the 200 series) it fits and focuses well on my 203FCC and my 500C/M

at one time, i bought a spare waist level finder that fit but was way out of focus on my 203TCC at the time; maybe they had an older version camera with a different focal distance to the GG?

 

[darr]

I tried it with a 50 and and a 80mm. I also tried it again with the dedicated CFV50 screen and it is out the same amount. I hear you on their return policy but unfortunately I only have the back for a week so that won't help me much, I have to use one of my NC-2 45 degree prisms for verts, not ideal but kind of works I guess.

To be honest I think someone pulled a fast one on KEH and swapped the glass out of a heavily corrected diopter and put it in the mint zero correction eyepiece, otherwise this makes no sense at all, it seriously looks unused. Back it goes for sure.

On initial testing the back seems to work well with most of my lenses, even the 80 has a nice look wide open, the 350 plus the 1.4 converter work surprisingly well wide open. One issue I have had though is that unlike my previous 500 CM bodies, the 501 CM's have a pretty stiff shutter actuation when using a cable release, so it induces more camera shake than I like and now I see that confirmed when using slow speeds on longer glass even using the mirror pre-release. This is nothing on the back, I just need to send each body in one at a time to have David Odess adjust one or both of them to take far less release pressure.

The back itself seems good, is fun and pretty straight forward to use although live view is a bit menu buried. Wish it had came with more than one battery though, maybe that is Hasselblad's way of keeping the click count down, lol! I am pretty sure the 12V charger from my Leica M240 will work since it uses the same plug, that means I can solar charge it on my camper while in the field. It only weighs 100 grams more than a loaded A-12 back which is nice.

The main thing the back and the kit has to do is in an overall sense at least equal my Nikon D810 with my better glass and it seems to. The goal here is for me to use the system I prefer to use for fine art in using much preferred black and white film and yet still be able to quickly put on a digital back and get an ad shoot done. The Nikon system just does not allow for that very easily since the negatives are no where near the size I need for quality darkroom prints. So far it looks like the CFV50c may solve that....

Now for the big shoots, a stringed quartet for an ad and a huge 14,000 x 40,000 pixel mural for a private commission.....

I have never used my 501CM outside of the studio, so I am shooting at 1/125 and higher with cable the majority of the time. That is an interesting point you make about camera shake from using the cable. I have made note of it and will be testing my body at longer shutter speeds.

The "P" button (CFV-50c) on the left is where you set it to Live View (or another task) for quick viewing. Once set, you never have to dig into the menu for it.

The batteries are SONY NP-F550 and easily found on eBay. I paid $37.99 for two OEM in 2014. There are many 'other than OEM' batteries available as well.

I use the back part time with the 501CM for studio macro and portrait work, and also with my tech camera and Schneider lenses. I also have a P45 that I need to sell!

Kind regards,
Darr

 

[Jager]

Following your thread with great interest, AiPrint. I'm also considering the CFV-50c and my use cases are similar to yours... ability to quickly switch between black and white (and the occasional roll of color) film and a digital back providing very high quality IQ. All on the V-system, which I love.

I'm wondering how the crop factor of the CFV impacts viewfinder ergonomics and lens choice. And I'd love to see any CFV images you might like to share.

 

[jlm]

here's one: cfv50, 60mm, 203fcc

 

[Jager]

Very nice pictures, jlm and AiPrint. Looking at the RAW files, how do they compare in terms of detail and tonality with high-end 35mm digital?

Darr (or anyone else), do you have any portraits you can share?

Interesting that you burned in the clouds on your scenic, in-camera, Ai. Do you recall what your shutter speed was that allowed you to do that?

Thanks again. Lots of very helpful information in this thread...

 

[steve_cor]

Very nice pictures, jlm and AiPrint. Looking at the RAW files, how do they compare in terms of detail and tonality with high-end 35mm digital?

Darr (or anyone else), do you have any portraits you can share?

Interesting that you burned in the clouds on your scenic, in-camera, Ai. Do you recall what your shutter speed was that allowed you to do that?

Thanks again. Lots of very helpful information in this thread...

With a negative in an enlarger, you could burn in the clouds. But with a digital back on-camera, you would want to dodge. Only way to do that is to use a neutral density filter.
There is no such thing as black glove in camera burning and dodging. That's why we use multiple exposure bracketing for HDR.


--Steve.

 

[ErikKaffehr]

Hi,

The trick is to expose for the highlights. So you expose that there is no clipping on the highlights, as much as possible at the base (normally lowest) ISO. The camera histogram should give good info on that, even if it is somewhat tweaked, as it is normally based on a tweaked image (curves and WB applied).

After that you apply a graduated filter to the sky. Lightroom 6 that I use have excellent tools for that. Taken care of the sky you would adjust the whole image to taste.

Shooting for the sky gives less exposure for the darker parts, so you can use a high quality split ND filter during exposure that darkens the image before capture. On the other hand, the CFV 50c should give you tons of shadow detail anyway.

HDR techniques help combine two or more shots in the same image. The HDR tool in LR is really good.

Anyway, the clue is a well exposed image, without blowing out the sky and doing good processing on it. Taming a high dynamic range is never easy, especially if you want a credible look.

I very often use RawDigger to analyse my raw images. That tool gives insights into how the raw is exposed without the trickery always present in raw converters.

Best regards
Erik

Interesting that you burned in the clouds on your scenic, in-camera, Ai. Do you recall what your shutter speed was that allowed you to do that?

Thanks again. Lots of very helpful information in this thread...

 

[steve_cor]

Ai_Print,
You have awesome technique, which you have proven. I especially like your mountain scene. I would have thought that fingers in front of the lens would come out as blurry fingers in the picture. Thanks for that info.

During the night, I dreamed that Sony made a new dodging feature. After you take a shot, you select dodging in the menu. Then you circle the area to be dodged on the touch screen. Then on the next shot, the sensor electronically reduces exposure to that area. Imagine that, the new Sony black glove in-camera dodging feature.


--Steve.

 

[Jager]

Ai_Print, any update on how you're getting along with the CFV-50c?

Did you get your PM90 situation sorted? Have you been able to get out and make any more images? Any thoughts on the back?

 

[JohnBrew]

I felt that battery life with the CFV-50c was very good, especially compared to the P45+ I tried. I wouldn't think you would need more than two.