Credo WS

[Egor]

My studio is considering purchasing another digital back for certain assignments related to both product work and outdoor landscape/architecture work.
Up until now we have been mostly sold on a Credo-40 (we have numerous camera systems all use Mamiya mount).
I am interested in user's opinions and reviews of the Credo WS (probably 60MP CCD); how they are used to get regular color as well as IR; pia factor when having to use various filters...etc.
We could easily just go with a standard Credo-40 for these needs, and pick up a used P45+ and have it converted to IR, so that is our other option. We do some IR landscape and architecture work that is gaining in popularity for our clients and want to give them a mfd quality aspect. Currently for IR work we use converted Canon 20D and 5D2's and Canon glass.

I can't find many reviews (any?) of the WS option and its practical use in professional studios like ours so thought I'd ask here.
Thanks in advance for any responses!
Best,

e

 

[kdphotography]

Eric, make sure you talk with Don Libby, who basically would not let the Credo WS out of his claws at the last CI in Lake Tahoe. I think the big difference is the ability to use Live View with the CMOS sensor, not the CCD version you refer to. Simple change of the filter on the lens, and you're shooting at that particular chosen wavelength. Both Don and I use Sony's converted to full spectrum, allowing you to shoot in color (hot mirror filter), full spectrum, or whatever IR filter range you select.

ken

 

[dougpeterson]

My studio is considering purchasing another digital back for certain assignments related to both product work and outdoor landscape/architecture work.
Up until now we have been mostly sold on a Credo-40 (we have numerous camera systems all use Mamiya mount).
I am interested in user's opinions and reviews of the Credo WS (probably 60MP CCD); how they are used to get regular color as well as IR; pia factor when having to use various filters...etc.
We could easily just go with a standard Credo-40 for these needs, and pick up a used P45+ and have it converted to IR, so that is our other option. We do some IR landscape and architecture work that is gaining in popularity for our clients and want to give them a mfd quality aspect. Currently for IR work we use converted Canon 20D and 5D2's and Canon glass.

I can't find many reviews (any?) of the WS option and its practical use in professional studios like ours so thought I'd ask here.
Thanks in advance for any responses!
Best,

e

Here's a post that covers some of the options for medium format infrared. The Credo WS is a cool marketing name for a Credo without an IR filter, and likewise we can provide any Phase One back without an IR filter.
Infrared and B+W Medium Format - DT Blog

We learned a lot about infrared photography as a result of our dedicated forensics/cultural-heritage infrared camera system the DT Multispectra. I also have some personal experience (infrared | Search Results | Doug Peterson) with infrared; the idea of imaging with unseen light just completely fascinates me.

As part of the research we've done we have the specifications for the IR-block-filter glass used in each model of Phase/Leaf backs, so that you can use the exact same glass (thickness and spectral profile) in front of the lens as you would have used in front of the back. Having the exact same filter in the form of a lens filter rather than a sensor filter is important since the color profiles for the back were developed with that specific IR-block-filter in place.

On longer lenses this brings you back to effectively identical color as you would get with a "normal" (visible only) version of that digital back. However, on wide-angle lenses the IR cut glass there is a slight introduction of color cast at the edges of the frame and a slight change in spectral transmission, so that even after an LCC you will not have identical color to what you'd get with a "normal" (visible only) version of the digital back. For most use-cases the difference is fairly minor (after an LCC is applied), but if doing, for instance, product photography or art reproduction this would be a significant drawback.

We also have the spectral transmission curves for a variety of other glass filters which we have normalized to the same scale for easy estimation of the net effect of stacking a particular Phase One back and filter together.

If it's possible budget wise, the CMOS based backs are excellent candidates for IR conversion as they allows you to focus quickly/elegantly in live view. When using the other backs I would suggest that the best use case is using a tech camera where the focus/composition methods are already based around not being able to see through the lens.

We also have recently gained access to a limited-edition 120mm lens which is corrected for both visible and IR light (out to around 1000nm) and for both infinity and macro via a floating element. This means significantly sharper results when doing IR-only and the option to shoot visible+IR without the typical slight diffuse halo around sharp details which contain a lot of IR content, even when shooting wide open. This also reduces complexity when compositing captures taken with different filtration (e.g. blending a visible only and IR-only image together in Photoshop). This lens is not available to the general public at the moment but we could have it mounted for an Arca R tech camera or on any brand of view camera. Due to some dimensional limitations I dot no think it would be possible to mount this lens to an Alpa or Cambo tech camera, but it would work on a Cambo view camera like the Actus.

The reason you don't see any reviews by pros is almost surely because there are only a handful of pro infrared-converted digital back users in the world. It's a niche within a niche within a niche. That said, it could be a nice way to provide a different offering to a client for whom the unique and unusual rendering of infrared is appropriate. I hope if you do go this route that you'll return to this thread and post some examples of the results!

 

[Egor]

Great info, I’ve been out and about doing family stuff…

Thanks, Ken, for the referral!
I don’t know Don Libby, but have seen his posts here many times. Hope he chimes in.

Yes, the CMOS chip and its LiveView would be a better experience, but I may not be able to justify the price for that end of my business just yet. Maybe if it does both...I have a rule in my studio that any piece of gear must earn 3x or more its cost per year to justify purchase professionally. Right now we are only at about $15-20k/year in IR related work. But that is increasing; maybe more with some new accounts.
So right now, either I build it into a studio purchase from the regular work of the studio ( thus the WS option) , or I buy an older P45 or even Credo40 and have it converted….
I am used to flying blind when shooting IR anyway, so it can't be as bad as it was in the film days

I am most curious about the filter changes and the pia factor especially for something like our new 40-80LS which takes a huge 105mm filter. Most of the time (90+%) it needs to be a normal visible spectrum killer MFDB
Doug’s info very helpful on that score, I think it won’t work well for us… We have a IQ250 but I don’t think I will convert it, (my studio mgr. would have a heart attack)…What say you, Don and Doug?
I have Mamiya DF+ cameras, Cambo D23 view camera, Sinar view camera with P1 sliding back…view camera lenses including 40HR, 120ASPH, 90.…etc.

Doug, thanks for the info! I checked out your blog posts on the subject. Great stuff!
I too, have been fascinated with IR. Even since I was a kid. I hauled the special “metal” film canisters and film changing bags around all over Europe when I lived there, and loved the whole “treasure hunt” of seeing what I shot usually days later…Everything had to be done in “absolute darkness”, including composing (filter was opaque), focusing (remember the little red IR mark?… loading the film, developing…etc. no such thing as “safelight” with infrared film. The results were always very cool and unique.
When digital came along, it was like a godsend for shooting IR…sooo much easier.
I used it professionally at first for architectural work, then later for landscapes and now forensics on certain art collections and high dollar investigative work. even saw three iterations of sketches behind a Chagall!
The 1st camera I had converted was a p&s Nikon and then every Canon I have owned since at the end of its life cycle in my studio.
Photos below with a mere Canon for a Maui developer they loved them and bought many more…fun gig! (and a free trip to Maui to boot!)

 

[dougpeterson]

With the 40-80LS there would be a large PITA factor to shoot normal color images for the two reasons you already know: 1) the required filter is quite large and 2) at the wider end of the 40-80 zoom range the IR block filter will produce a slight blue cast in the edges of the frame which require an LCC to correct

I'd suggest a Credo 40 or IQ140 if the budget doesn't allow a CMOS back. The P+ series LCD was not great for focus review, which is even more important for IR work than color work.

In comparison to your converted Canon both will absolutely knock your socks off. IR on a color sensor really stretches the sensor and raw converter to its limits; on many cameras most of the IR response (at most spectral bands) will be on the red channel only which is only 1/4th of the total pixels, while the green and blue will be very underexposed. Without great dynamic range and excellently paired raw processing the result is usually very noisy, soft, and full of digital junk like banding and artifacts highlights. The Credo/IQ140 would improve hugely over your Canon in this regard, as there is, relatively speaking, a more homogenous response on the other channels past 700nm and there is enough response and fidelity in the shadows of the green and blue, and enough intelligence in the raw processing in Capture One when using radically unusual white balance values, to handle these limitations-of-input with significantly more elegance.

 

[Don Libby]

I had the chance to use a WS earlier this year in Tahoe and almost didn't give it back. While I'm not a fan of CMOS sensors they do have their value for IR and liveview. I ended up using this entirely on my Cambo WRS and 40 HR as I happen to have the correct size IR filters (also have a Sony a7r converted to WS).

My experience using WS is based on using a hot mirror filter for color, as well as a choice of IR filters such as 520, 720 and 830. Getting proper white balance is the key to everything especially IR/WS work and once you have a working flow it becomes much easier.

I tried using it on my DF however found that it didn't play well as it behaved more like a non converted camera (couldn't see through the viewfinder). I'm uncertain how live view would have worked as I didn't try it and returned to using the WRS.

The 40-80 has a filter of 105mm and while not impossible to get will be expensive (I've actually looked into this a little). Now with the XF being released and soon to be able to play well with Leaf I'd like to think the minor issues I had using the WS with the DF are gone.

If we get to the point where I can attach a WS back to the XF and afford the cost of the filters for the 105mm filters then I just might rethink getting it.

I really enjoyed the ease of use with the WRS and have to say became somewhat spoiled using LV to set the shots up.

Sorry for delay in responding however I'm currently in Sedona for a wedding before heading to Bryce and beyond. If I think of more then I'll attempt to add it as time permits.


Don

 

[Egor]

Thanks, Don!
Couple o questions when you (or other forum member) got time to answer:

1. Whats a "hot mirror" filter and how is it different that any other kind of filter? (I guess I could google it if thats a waste of everyone's time...sorry, like Sam Clemens said "Everyone is ignorant, just on different subjects"

2. Why were you unable to see through your DF viewfinder? Is there something else going on here I am not aware of? (probably fersure I know But even my converted Canons have no problem viewing thru viewfinder, or live view for that matter. They are even adjusted for proper IR focus onto the sensor! I assume too much for MFD?

3. What is the advantage gained by using the XF body? Or are we comparing to a regular DF as opposed to a DF+ (serious improvements made to LV functionality)

4. What are the filters needed to use the 40-80LS? We talking Lee filter holder and 110mm stuff? What do those babies cost?

I am thinking the more I read here (glad I asked) that it may be cheaper and better in the long run to have a dedicated IR camera or maybe even just convert my existing IQ250...do the job...convert back. I don't know how much that would cost me but I am guessing it wouldn't be as bad as $30K/yr. :scry:

Best,

e

 

[yaya]

Eric I have a largish collection of images I've shot on a Credo 60WS with different filters from 695-950nm. Some are landscapes and some are cultural heritage stuff like old masters' paintings. Email me if you'd like to see some of those. If you're looking for a specific type of image I can probably produce one, inc. on a tech camera as I have an Rm2D with a 50mm lens and all the necessary step-rings.

We can supply IR cut filters (similar to the ones or standard backs) in 72mm & 77mm diameters (threaded) as well as a 100x100mm

The majority of these backs go into cultural heritage, mostly conservation and restoration of fine art work, manuscripts etc. in museums and archives. And there are also a few freelance pros who work with these institutes.
René Gerritsen is one of them, here are his impressions: Link

And there's a piece written by Andy Finney a couple of years ago on the infrared100 website: http://www.infrared100.org/2013/08/60-megapixels-of-near-infrared.html

Let me know about the images if you want, need any

Best

Yair

 

[Egor]

Thanks, Yair
As always, that is great info.
I will PM you soon to see some add. samples and discuss when you have time.

It was great to read about others doing the same as Doug put it: "a niche within a niche within a niche"
I like it as it gives my existing clientele another reason to use our studio that they just can't get anywhere else (unless they really dig deep for it, which in some cases means a call to us anyway and I can refer them)
Very impressive research from René, sounds like someone I would really enjoy a chat with
Best

e