Topic: 35MM full frame CMOS back for MF tech camera (Read 7408 times)

Clyde RF · « **on:** February 19, 2012, 05:36:55 pm »

I am wondering why no manufacturer (such as Sony) has ever come up with a full frame 35mm cmos digital back for mf technical cameras, complete with live view and focus peeking, minus the irrelevant bells and whistles associated with dslrs. While small format high mp sensors would not match the IQ of medium format backs, a means would be provided in the application suggested to have the ever more needed movements, without having to go to s+t lenses. The tech cameras would allow very precise, convenient, and versatile movements--on all lenses, at a cost that would probably be less than to acquire a full stable of the best t+s lenses. Obviously there would be no coverage problem with extremely sharp Rodenstock and Schneider lenses, and I would think that the expense of such a back could still be quite a bit less than that of good quality used mf backs. I am aware of the fact that some view cameras are available which utilize an inserted whole dslr, but there are additional limitations therein, and to use a local expression; that approach would seem to be like going all the way around the hog's rear end. Since I have never seen any other reference to this (to me) seemingly obvious application, I may be missing something major. If so, I hope the aces on this section will not see this question as being like--why can't I grab the seat of my pants, and lift myself off the ground? Any thoughts are appreciated.

Regards, Clyde

BernardLanguillier · « **Reply #1 on:** February 20, 2012, 01:59:45 am »

Something like this?

- http://www.komamura.co.jp/e/digital/LD.html
- http://www.camerafusion.com/SB01ProductBrief.pdf
- http://www.fotodiox.com/product_info.php?products_id=634

Cheers,
Bernard

torger · « **Reply #2 on:** February 20, 2012, 02:55:23 am »

I've thought about the same thing, but there is probably too small market to do it. There are DSLR adapters, but obviously they work only for macro and product shoot type of applications due to the mirror box.

It would be equally possible to make a much lower cost MFDB, the large sensors are indeed expensive, but still only a fraction of the price of a MFDB. The market is made for professionals and if you can make your living out of the photography, putting the leasing cost of a MF system on top is not too hard.

To make a low cost MFDB successful one must sell to amateurs in large numbers. If selling only to professionals like today the price must be high or else the development costs will not be covered, there are simply too few professionals that need MF rather than pro 35mm DSLRs. This makes a low cost digital back a very risky product, and the current MFDB companies are probably too small to take such a risk.

Gary Ferguson · « **Reply #3 on:** February 20, 2012, 03:43:45 am »

I've been using a medium format digital back on a technical camera for several years (P65+ with a Linhof M679cs), but even so I'd be the first to recognise it's not a happy marriage.

The key reason is that you generally enlarge the MF back images more than you would a 4"x5" film back, and it's the enlargement that causes the problems.

Basically once you use a loupe stronger than about x6 or x7 all you see is the grain of the focusing screen. This degree of magnification/enlargement works fine for 4"x5" film but isn't quite enough for a MF back, you'd really need a loupe of about x15 to handle lens movement focusing with real precision. For a 35mm sensor (at least one without live view) the problem gets much worse, the enlargement/focusing/loupe magnification equation goes from "comfortable" on 4"x5" film, to "testing" with a MF back, to "inadequate" with a 35mm sensor.

John R Smith · « **Reply #4 on:** February 20, 2012, 04:22:17 am »

Gary has just nailed the snag . . .

J

torger · « **Reply #5 on:** February 20, 2012, 04:37:38 am »

A 35mm CMOS-based back would have a great live view with 10x zoom, just like any modern 35mm DSLR. Those sensors work great for live view unlike large CCD MF sensors (although the latest backs have some sort of live view). Anyway, ground glass would not be used with such a back, focusing would be made via live view.

yaya · « **Reply #6 on:** February 20, 2012, 10:18:54 am »

Quote from: Clyde RF on February 19, 2012, 05:36:55 pm

a full frame 35mm cmos digital back for mf technical cameras

The Leaf C-Most was introduced in 2001 and was followed by the Valeo 6 and at the time it was considered a very affordable digital back. It worked pretty well on view cameras with Live View (tethered) except, as Gary suggested, the limitations when using wide angle lenses....since they're not that wide with a small chip

Unless you use a Digiflex or a Cambo Miniwide with Nikon lenses...

I see no sense for the 35mm manufacturers to invest in such a project, it doesn't fit their business model...

Yair

Clyde RF · « **Reply #7 on:** February 20, 2012, 06:05:06 pm »

Thanks for the responses everyone. I will try to further clarify my thoughts relevant to my above post. In coming from 4 by 5 film view camera use, I would like to avail myself of the advantages of digital, but not being a pro, the cost of any eminently usable mf back is too much of a stretch for me at this time. With the advent of the new high mp sf backs (36mp and maybe soon 50+mp), I have hope that with said back, I would be able to come up with prints of a size and quality that my view camera cannot entirely put to shame. However--focus stacking and other digital maneuvers non-withstanding--I am just not willing to give up movements, as I do almost entirely landscape work. As most of you know, movements are especially appropriate to preserve IQ and still have depth of field versatility while dealing with sf's more open aperture requirements. I realize that t+s lenses are often an excellent solution for many whose work centers around the use of dslrs, but with landscape in mind, a lot of bucks can be sunk into obtaining a number of them (especially Schneider and Hartblei). Technical cameras are very appealing to me for a number of reasons, and if I had one I would hang on to it if only because of hopes to later on be able to manage acquiring a mf back. Then again, I don't want to drop from 4 by 5 to mf film. So we come to the point of this post. I believe that a live view equipped sf high mp cmos back on a tech camera would keep me happy for a long time. The real questions seem to be: 1. Would there be enough others having needs overlapping mine to justify development costs of the product being described.2. How much of a stretch would be required for a company like Sony (often up for tackling new angles) to put the necessary part of the tech already developed in a new camera into a precision frame to be used on tech cameras. Conversely, maybe a company like R.R.Stuff could take already developed camera sensor technology, and put it into a tech camera back. What are your thoughts?

Regards, Clyde

andyptak · « **Reply #8 on:** February 20, 2012, 06:57:12 pm »

Haven't I seen adaptor plates for 4 X 5 cameras and Nikon/Canon/Sony mounts (for the entire camera, sans lens) on eBay? Similar kind of thing, isn't it?

alan_b · « **Reply #9 on:** February 20, 2012, 08:21:51 pm »

You seem to be somewhat price-sensitive, and I guess the imagined user base for a project like this would be as well. (Relative to current mfd systems). A few points/questions come to mind:

1. Movements require more precision the smaller the format. Look at current tech cameras like Arca, Alpa, Cambo and imagine how they could be scaled down and priced lower.

2. The least expensive digital view lenses are the "classic" Schneider Digitars, the widest being 24mm. A new system would probably need an additional shorter lens. Now compare the prices of these lenses in focusing mounts to current dslr t/s lenses - not much opportunity for cost savings there either.

3. How big would the market for this system be? How much demand above the existing used mfd/tech camera supply?

4. The X factor - look at some of the gotchas showing up with the IQ180 and certain wide lenses for example.

I don't see it happening, as cool an idea as it may be.

Clyde RF · « **Reply #10 on:** February 20, 2012, 09:30:35 pm »

There are adapters to allow complete dslrs to be fitted into view cameras (not technical cameras) to be used with lenses with greater coverage to allow movements, but the focal length range of usable lenses is more limited in this situation. I was hoping for sf sensors inclosed within only the back, to be attached to the same fixtures as would be mf backs. It would seem that this solution would be more precise, versatile, and simpler, lighter and more compact and convenient. I can't understand why this approach would be so difficult to bring off, as the sensor technology would already be there, and all the extras in a whole camera with the same sensor tech would not be needed. Of course any new production set up would incur some additional cost to employ, but once this was accomplished, I would think these sf relatively high res backs could be made available at a quite reasonable price. A manufacturer would obviously have to make a prediction as to whether the potential profitability numbers would justify the initial production costs. I see and hear a good bit about those like myself who are wanting to use digital tech cameras, but are at this time held back by the expense of of mfdb's. I'll welcome all opinions on this subject. I am most cost sensitive (initial cost+depreciation) about the one extreme (to me) expense of mf tech cameras--that of the mfdb. Naturally, no relatively hi-res landscape system is going to be cheap. However, an Arca rm3di + vario-finder would not set one back more than 2 Schneider or Hartblei s+t lenses, and have other obvious advantages. The precision of the Arca should be sufficient for any sf digital needs. The Arca R series calibrated lenses are big bucks, but I would go no wider than 43mm, and get by with very few. One of my major considerations is the depreciation factor concerning all digital backs; modular cameras and especially lenses do relatively well therein. The mfdbs are fabulous products. I wish I had the income to be able to afford one.

torger · « **Reply #11 on:** February 21, 2012, 03:16:23 am »

It is a bit unfortunate that the second hand market for professional digital equipment works in the way that prices are kept high until the equipment has been obsolete for a year or so, then it goes rock bottom. But then it is obsolete so nobody wants it...

I still think that it is not the sensor size that hinders the price from being low, oh well, if we say we're in the range of $6K. It is the business model. Low volumes, high service to pro studios only. It may be possible with a different business model with higher volumes and lower prices, I think many advanced amateurs would invest in medium format if price/performance would be better, but it is an enormous risk for the relatively small medium format companies to take and would undermine their current business.

I'm researching 4x5" large format, and while looking at that I think that a relatively low risk product would be a low cost 4x5" scan back designed to work in analog 4x5 systems. The pro market for scanbacks is near dead (so there's not really any existing business to harm), and I think the 4x5" amateur culture plus some pro studio product photo would make a modern affordable scanback feasible. There's no need for large expensive sensor tech in a scan back either. An advantage of 4x5" compared to MF digital is that lens cost is much lower, less complex lens designs, precision traded for size.

ondebanks · « **Reply #12 on:** February 21, 2012, 06:01:24 am »

If you look at a CSC mirrorless body like a Sony NEX, you have a high performance CMOS sensor which is very much more "exposed" than the sensor buried deep behind the mirror-box in a DSLR. While not quite like the completely exposed sensor of a MFDB or a sheet-film holder, it is "getting there" in terms of not obstructing/vignetting movements. It also has a much shorter flange distance than a DSLR, allowing in theory for much shorter focal length optically true wideangles to be used.

But the sensors are all APS format - for now.

So what I think may well happen - and I don't believe this is at odds with the business model of the likes of Sony or Canon - is for the next generation of CSCs to have "full frame" sensors. (People have wondered what's keeping Canon from announcing their own CSC - maybe this is why?). Slap one of them on the back of a tech camera, and I think it would come close to your requirements.

Meanwhile, you could experiment with say an NEX-5N body, prototyped to a tech cam lensboard.

Ray

yaya · « **Reply #13 on:** February 21, 2012, 08:08:52 am »

One thing worth noting is that all these high performance CMOS chips are heavily microlens'ed to increase sensitivity

You already see some cast issues with D3X etc and some wide-angle and T/S lenses. I expect the D800 (<4.9µ) to be worse still

So to mate them to e.g. wide-angle Digitars can lead to all sorts of problems

None of the 35mm manufacturers currently offer a hardware/ software based solution and neither does Adobe, so they will have to rely on Phase One to maintain and enhance the LCC functionality in Capture One

If you need movements with long-ish lenses you already have several solutions, the best one is probably the Cambo X2-Pro

And current wide angle lenses from Schneider/ Rodenstock are only wide if you're using a big sensor...

So again...not going to happen...you're better off looking for an entry level MFDB (used or new if you can stretch it), or stick to a 35mm FF body with T/S lenses

Yair

torger · « **Reply #14 on:** February 21, 2012, 08:24:33 am »

RawTherapee has had LCC correction for some time:

http://www.luminous-landscape.com/forum/index.php?topic=50990.0

yaya · « **Reply #15 on:** February 21, 2012, 09:42:35 am »

Quote from: torger on February 21, 2012, 08:24:33 am

RawTherapee has had LCC correction for some time:

http://www.luminous-landscape.com/forum/index.php?topic=50990.0

Indeed but it is not exactly a mainstream, off-the-shelf product (no offence to the authors) and it is not supplied by the 35mm manufacturers....

simonstucki · « **Reply #16 on:** February 21, 2012, 03:01:28 pm »

would love that (I actually had this dream since quite some time). equip it with a shutter and make it possible to use regular mf lenses (pentax, mamiya (6, 7!), hasselblad and so on) that would be great. of course you would need some ww lenses. lets say a affordable 24/5.6 and a 30/4 or something like that. for the longer lenses you could just use what is already available. of course it should also be compatible with alpa lenses or arca swiss that would be great. oh and please make it 4x5 (not the size, the aspect ratio of course aprox. full frame area would be great).

please somebody make that

Clyde RF · « **Reply #17 on:** February 23, 2012, 05:43:16 pm »

Well, it seems that there will be no outburst of optimism out there concerning the possibility of a fairly hi-res sfdb becoming available anytime soon. This is a frustrating consideration for me because there is no solution available at this time that would come very close to providing a similar degree of portability, precision, versatility and cost effectiveness, as would a tech camera (Arca, Alpa, Cambo etc.) equipped with said sfdb. I checked out the Cambo x-2 pro which seems to be an attractive unit, but lacks all in plane shift and rise/fall, suggesting that it would have potentially less of the even more needed precision associated with a smaller than medium format back, and it provides less lens choice (I would prefer to be able to go longer than 150 mm plus have something in the 43-55 range). The x-2 pro also weighs 4.6 lbs. compared to the more precise and versatile Arca rm3di which comes in at 2.36 lbs. To my knowledge, complete small format cameras cannot be implanted into tech (pancake) cameras, but only into the less precise and much bulkier view cameras. I have difficulty being enthusiastic about the very concept of hooking one camera into another. Above and beyond the bulk consideration, it is a well known fact that inserting anything (which does not do good) into the functioning path of a device (imagery, sound, etc,) will always to some degree degrade the final result. I would not want to be restricted to riding in my car only when it is being carried about by a car hauling truck, and I have never taken to wearing my shoes while they are still in the boxes they came in. I have already commented on my preference for tech cameras over t+s lenses, so I guess I am left with relying on my 4 by5 view camera for now. Torger's suggestion about a new scan back is interesting and seems to have promise. As it can be seen that I continue to run every idea through the gauntlet--a limiting factor for me with a scan back would be the banding problem with ambient outdoor light. However, on certain rare days in springtime, when there is full cloud cover all day long but the sun is constantly visible and faint enough to be looked at, a scanning back would be the perfect thing to have. I thank everyone for their response--good news or bad (or in between) it all helps me to move closer to a decision I will eventually have to make.

Regards, Clyde

NicolasBelokurov · « **Reply #18 on:** February 24, 2012, 09:57:14 am »

Quote from: BernardLanguillier on February 20, 2012, 01:59:45 am

Something like this?

- http://www.fotodiox.com/product_info.php?products_id=634

Cheers,
Bernard

I just checked the fotodiox adapter and the camera fusion PDF, looks like a well made product and a curious idea, BUT considering for example a 75mm lens on a 4x5 camera that is equivalent to a 21-24mm lens on 35mm, I wonder exactly how many frames can be made before the mount on a DSLR begins to obstruct the image produced by the large format lens.
In different words, by using one of these adapters, what would be the widest panoramic image possible?
Any thoughts?

JohnTodd · « **Reply #19 on:** February 25, 2012, 07:01:00 pm »

I seem to recall that some sensors are actually constructed of more than one slab of silicon - I think I heard that the Canon 1D sensor was made in two halves. That made me wonder about my Aptus 22, which seems to have a clear divide down the middle, and has the suspicious dimensions of 48 * 36 mm, i.e. it could be two 24 * 36 sensors set side by side. If that were the case (and allowing that the sensor packaging would have to support it), why not go for two 'old technology' Canon 5D2 sensors side by side, or eight 7D sensors at 59.6 * 44.6 mm?

(What I'm getting at is, given the fairly fixed size of the interface plate, screen, memory card, electronics and battery, why not cram as much sensor onto the unit as possible?)

Author Topic: 35MM full frame CMOS back for MF tech camera (Read 7408 times)