Contax 645 and digital back

[thsinar]

Dustback,

It does make a sense to point this out, that adapter plates are not the faulty link in this focus error, but the body, since it has been claimed that it should be a reason to go with backs with a dedicated mount. Our experience is, that each time when there was/is a back- or a front-focus it was due to a mechanical issue with the camera body.

And, as you point it out yourself, with dedicated mounts you can't correct this.

Best regards,
Thierry

It is pointless to claim whether that is due to the body or the adapter since the result is the same. focus error.

If the body is out of spec theoretically you will experience the same problem with a fixed mount back (have never had it), at least with an adapter you will have the opportunity to tweak it yourself.

Anyway don't let it refrain you from getting a system with interchangeable adapter plates.
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[Dustbak]

I think you are reacting with the wrong arguments. I also don't believe it is always the bodies that are out of spec. It does matter how fast you tighten the adapter plate. I have found bodies where I could overtighten and loose infinity, loosen half a turn and I got it back (or was it the other way around, I can't exactly remember). Hard to say who or what is out of spec. I believe there is not always such an absolute thing as either the adapter being wrong or the body, it is the combination of the 2 and there are more parameters than just the body & adapter. Besides that, it is always the result that counts.

For the people that are freaked when focus is not entirely where it should that don't want to adjust their own cameras it doesn't matter which part is not right. The only thing that counts is the fact that focus is not right. For those people an adapterplate system might not be the right choice. That is what I meant with pointless to tell that it is probably not the adapter that is the culprit. It is highly unlikely that the adapter is at fault.

With an adapterplate system, you as an end-user have an additional point to take care of. You have more control over your own system which also means another place where you can get it wrong. For some people this works, others absolutely prefer to have everything handled by someone else (dealer, manufacturer, etc..).

I love the adapter plate system but it is something that can go wrong even if it is easily fixed. Again if that is not your cup of tea than maybe you should not get into a plated system (unless you plan on never taking it off again   )

[thsinar]

I did not want to argue with you Dustback, and I understand well your point(s).

I can't just let it said, that one should go for a back without adapter plates because it leads to problems: that's absolutely not right to say this.

Best regards,
Thierry

I think you are reacting with the wrong arguments. I also don't believe it is always the bodies that are out of spec. It does matter how fast you tighten the adapter plate. I have found bodies where I could overtighten and loose infinity, loosen half a turn and I got it back. Hard to say who or what is out of spec. I believe there is not always such an absolute thing as either the adapter being wrong or the body, it is the combination of the 2 and there are more parameters than just the body & adapter. Besides that, it is always the result that counts.

For the people that are freaked when focus is not entirely where it should that don't want to adjust their own cameras it doesn't matter which part is not right. The only thing that counts is the fact that focus is not right. For those people an adapterplate system might not be the right choice. That is what I meant with pointless to tell that it is probably not the adapter that is the culprit. It is highly unlikely that the adapter is at fault.

With an adapterplate system, you as an end-user have an additional point to take care of. You have more control over your own system which also means another place where you can get it wrong. For some people this works, others absolutely prefer to have everything handled by someone else (dealer, manufacturer, etc..).

I love the adapter plate system but it is something that can go wrong even if it is easily fixed. Again if that is not your cup of tea than maybe you should not get into a plated system (unless you plan on never taking it off again   )
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[Dustbak]

That I absolutely agree with.

It is not the adapterplate system but the user (in most cases), unfortunately we all have the tendency to blame our equipment when we screw up

[HAK]

Had the same question for my Contax, decided to invest more than I initially wanted in a refurbished P25 and I'm more than happy with the results I get. Have a look at my post

http://luminous-landscape.com/forum/index....ndpost&p=181049

which show some recent low light results.

Don't make the error of investing too little in the back: you will regret it very fast and find out, that you threw your good money out of the window.

[eronald]

Thierry,

With all due respect this type of statement is called "vendor fingerpointing" and is extremely frustrating for the client. Saying "our experience is that we have never made a mistake" is not believable, and gives you a reputation for arrogance.

It is certain that the adapter system gives the client added flexibility, provided he is supplied with the tools to measure the focus and get the screws tightened just right. A mechanical system which separates the act of fixing the back to the adapter and the adjustment of the focus would however be an improvement.

Edmund

Dustback,
Our experience is, that each time when there was/is a back- or a front-focus it was due to a mechanical issue with the camera body.

And, as you point it out yourself, with dedicated mounts you can't correct this.

Best regards,
Thierry
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[Dustbak]

Working with adapter plates I would love to have the following system.

Instead of fixing the adapter onto the back and shimming (if necessary). I would like to fix the adapter to the body and shim it (again if necessary).

The back can be attached to the adapter via a 'regular' attachment system like the fixed mount backs.

The advantage over this is that you can attach mounts to different bodies and leave them on, especially if they are shimmed it is a lot faster. Swapping cameras will become faster and the 'risk' of screwing up your focus is gone.

Naturally, the sensor will be a bit more exposed but this is also the case when swapping adapter plates (though that will happen less often). A good cap would be necessary to be able to store the back when not mounted on a body.

[thsinar]

Edmund,

also with all due respect, I think you are going a bit too far by saying "vendor fingerpointing" and "our experience is that we have never made a mistake": I guess I don't have to make any proves as to being a vendor or not, nor do I need to be called an "arrogant". I try to provide accurate and true information here, that's all.
And when I claim what I have claimed in my previous post, it is because this is what I believe to be true. If in addition to this, I can convince someone that the Sinar products are matching their needs and expectations and are ready to go with it, I am the first, obviously, to be happy of this: I guess there is no secret and no shame in this.

Then, I would suggest you to take a Sinarback eMotion and try to screw an adapter at its place: I am sure you would understand then that there are not 2 ways to screw and tighten the adapter.

That there are mistakes made by Sinar, that something can't go wrong during the production, that an adapter in a batch is not right and up to the tolerances, that is obvious. But if an adapter has the right tolerances, then the focus problem simply can't come from this part. Period.

I don't understand why I have to constantly have to justify myself in front of you: I am here to make my "work" honestly and with the information which I believe to be true.

Best regards,
Thierry

Thierry,

With all due respect this type of statement is called "vendor fingerpointing" and is extremely frustrating for the client. Saying "our experience is that we have never made a mistake" is not believable, and gives you a reputation for arrogance.

It is certain that the adapter system gives the client added flexibility, provided he is supplied with the tools to measure the focus and get the screws tightened just right. A mechanical system which separates the act of fixing the back to the adapter and the adjustment of the focus would however be an improvement.

Edmund
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[Colorwave]

I'm shopping for a digital back for the Contax 645 system I just bought to shoot fine art reproduction work, for my large format printing business I'm launching to print for others, plus for landscape and macro work for my own work.  Because of budget reasons, I will be living with a 22MP or smaller back, stitching images for more demanding large prints that require it.

I've been leaning toward a P25, since most of the advertising photographer clients that I do modelmaking for now are Phase One users and I'm most familiar with Phase.  That said, there seem to be some good deals right now on Imacon backs.  Can someone tell me if the Contax will play well with the Imacon Ixpress 528C or 384C with the 4*Res capability?  I don't know what sort of communication is required between back and camera for multi-shot.

I understand the limitations of multi-shot for many things, but find it intriguing for the art reproduction and macro work that I want to do.  Even the square sensor, 16MP 384C can generate 384MB files with 4*Res.  Do those 384MB from a multi-shot back hold up reasonably well, assuming movement is no issue, to similar file sizes from a single shot back?  I haven't seen any RAW files from these backs, and these aren't popular rental items in my market.

Thanks,
Ron

[Dustbak]

I use a 384 for clothing. The files in 4shot are absolutely stunning. No moire, no color artefacts & amazingly sharp. In 16shot it can produce 64MP files however you need to have a totally stable environment. There is no single shot back that can deliver a similarly large file. Under perfect circumstances it delivers a large and better file than my CF39 (39MP back). The 39 delivers moire in many cases, no such thing when doing a 4shot on the 384. Having said that, the 16shot mode is something that you don't use that often. Not only is it slow but chances are pretty big it will turn out a bit soft in which you need to downscale it to hide that (50% is still around 30MP so it is not that bad). Again it is slow.

Both 384 as well as the 528 work fine with the Ixpress Contax adapter on the Contax.

For the type of work you are mentioning I believe the 528 would be a much much nicer choice than the P25.

You might also want to check out the Sinar 54H (which is the multishot version of the sinar).

I use the Imacon on H & Digiflex, have used it on V and other exotic stuff. I will be upgrading the 384  to either 528 or CF22MS (if I get a quote of one the Hasselblad dealers) this year.

[rljones]

my e75 back has proper focus on two different Contax 645 bodies.

even a temporary loaner back had no issues; i used the same shim and adapter plates on both backs with both 645 bodies. zero focus problems.

and with the same adapter, no focus problems when used on an Alpa 12.

btw, thierry and steve hendrix have both been very helpful when i have concerns.

-robert

[evgeny]

Dustbak,

can you compare 384 vs P21 ? Image quality, battery life, ease of use of software, work in studio and outdoors, etc. Thanks!

[Dustbak]

Pfff....

Two totally different beasts. I have never worked with the P21 (I did use an A17). The P21 is self-contained and has a screen which is the biggest difference with the 384. It also has a 3:4 ratio where the 384 is square.

My 384 needs to use at least an image bank and has a monochrome screen that shows at best a histogram and the menus.

I have no problem using the 384 in the studio or otherwise indoors (studio-like setting). If mounted on a tripod and being able to do 4-shot there is no comparison (at least not between the 384 & A17) the 384 is the way to go.

If you need to go outside and move around freely I would definitely not go for the 384 but would probably prefer the P21 (or something like it). I hate walking around with disks in my pockets and wires running through my clothes.

Software is something you simply have to get used to. I have been working with all sorts of raw converters. I mostly get as fast as possible to something that I can handle in PS and take it from there. Most raw converters have things going for them and things that annoy the hell out of you. However with some effort you can get them to work for you in most cases.

Batterylife; I hardly use the 384 with only the image-bank. In 99% of all cases it is tethered to either my laptop or my studio machine. I have never used a P21 so cannot say much about its battery.

Again, you are comparing 2 totally different pieces of equipment.

[evgeny]

I see, thanks.

[samuel_js]

Dustbak,

can you compare 384 vs P21 ? Image quality, battery life, ease of use of software, work in studio and outdoors, etc. Thanks!
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The P21's battery life is really good . I can't say exactly but 3 to 5 hours in normal temperature conditions continuous shooting is normal. But of course, it depends how fast how cold etc...