View Full Version : Canham Traditional 6x17 back unique or generic?

emo supremo
11-Mar-2010, 21:28
I've acquired a 5x7 traditional and am wondering about the 6x17 backs. Is there something special about the Canham back or will, for example, that DaYi 6x17 back fit just as well?
While we are on the subject, what about the Horseman 6x12 backs, would they fit the Tradional or is there something querky I don't (but should) know about?
Man, what a great camera. It would be nice to continue to use the half dark slide so it's on to 4x5 color emulsions when my Portra runs out.

Paul O
12-Mar-2010, 01:08
The Canham film back is sized to fit the larger rear frame of a 5x7 camera - the Day Yi/Shen Hao/Art Panorama film backs are designed to fit the smaller rear frame of a 5x4 back so the only way of using these is to put them on a 5x7 - 5x4 reducing back. This is the same solution if you want to use the Horseman 6x12 film backs too. Do yourself a favour - get the Canham back! I use one with a Walker 5x7 XL and it is extremely well made, holds the film flat and the only "issue" is that it requires a battery to operate it and these can run down quickly when shooting in low temperatures. However, it uses easily available 9V batteries.

12-Mar-2010, 04:22
There is a Shen Hao 6x17 back for 5x7 cameras too:


Paul O
12-Mar-2010, 07:14
I stand corrected :o

Dave - Landscapes
12-Mar-2010, 20:09
Good advice on the 617 Paul and Dave. Now, the Horseman 6x12 back can be used with the 4x5 reducing back with one limitation! It is an excellent back and will fit perfectly under the GG (use protector so you don't scratch the GG). The limitation is that you need to remove the back to wind it on between shots because of the lever mechanism. This is not a problem if you don't bracket your exposures. If you do a lot of bracketing, then it could be a PITA. One of the other backs available with knobs instead of the lever may be better in that case.

BTW the 5x7 Traditional is a fantastic camera and I use the Canham 6x17 back with it.



emo supremo
14-Mar-2010, 04:13
The news on this end was well received because you shared experience(s) that would not have occurred to me. I missed Ed Brock's offering a few weeks ago and just after his yet another on deebay. Cost is always an issue but that Shen Hao is a well built camera. Having never seen either up close I don't know which I'd want to bang around on the trail in my rucksack. This is going to be hard acquiring one sight unseen.
Maybe this question deserves a new thread: has anyone ever mounted a Shen Hao 6x17 back for 5x7 cameras http://www.bhcamera.us/shenhao-spc617.html on a Canham 5x7 Traditional?
Thank you again for helping me sort this out.

Paul O
14-Mar-2010, 05:06
I can't comment on the Shen Hao 6x17 5x7 version - didn't even know it existed :o
However, I have used a number of 6x17 backs on 5x4 camears and having looked at the image the roll film holder appears to be very similar to the regular version that is used on 5x4 cameras. The main difference is that it locks in place onto a larger, flat plate in a similar fashion to the Canham. The major drawback with the 5x4 version is that the design requires the filmback to be extended somewhat to allow for coverage - this restricts the range of lenses that can be used. I managed to use 90mm (on a recessed panel) through to a 180mm before cut-off became an issue.

The 5x7 version appears to add no extension as it is simply a film carrier and adapter plate therefore in operation it should be no different than the Canham. She Hao products are good value for money BUT they are not built to the standards of other (Western) manufacturers. The Shen Hao is simple to operate and has very little that can go wrong with it. From first impression the Shen Hao back is probably the same 6x17 film transport mechanism as the 5x4 version - the few I tried all held the film flat, had no issues with frame spacing and were "well-built" in as much as they could probably be used to hammer nails into wood!

The Canham has the benefit of automatic frame advance - but does rely on a battery to operate it (a problem in freezing temps) and it is superbly crafted! The back can also be used with a PC cord from your lens shutter to the unit which will automatically wind on the frame between exposures; however, this only works with exposures shorter than 1 second.

The Shan Hao back is certainly cosmetically re-vamped compared to the 5x4 version - this has tiny bolts with hex nuts everywhere holding the back together - I managed to lose a bolt from just above the film take-up chamber halfway through a trip to Iceland - luckily no major light leaks! The method of attaching the film back has been improved too - the 5x4 version relied on flexing a pair of thin metal plates to lock the film back in place - the 5x7 version appears to use locking Graflock-type locks/bars; much more secure!

I'm not sure what the cost of a Canham is compared to the Shen Hao - personally I would get the Canham but if funds are tight the Shen Hao will probably do an admiral job too!

emo supremo
15-Mar-2010, 01:38
How can one thank you for such time expended on our (my) behalf? This is going to be a tough chestnut; given the benefit of your shared experiences both seem up to the job. It's a comfort to know now that throwing money at the problem is not the solution. Your point about the batteries makes me wonder though about what to do when the motor dies on a Canham...? All things mechanical break. Point is having wrestled 120 film on to spools of developing tanks or inserting the !@# bits into Epson's V750 scanner's !@# holder I'm a bit suspicious of anything that has to wind the snake-y stuff in the dark. Without jamming.
Another thing that I haven't factored in yet is weight. I need to research the weights now of the two choices. How many loaded 5x7 cassettes can I carry before I've equaled the weight of as your irreverent humor puts it, "Carry something you can bang a nail in with" More weight. Ugh.
With regard to restriction of choice on the lens. Paul, I take it from your first paragraph that putting a 6x17 120 film holder on a 5x4 reducing back mounted in a 5x7 camera gives an UPPER or LOWER of 180 & 90mm respectively? Is this correct? (that is to say, we are not talking about the 6x17 on a 4x6 camera, right?) Your comment, "...the design requires the filmback to be extended somewhat to allow for coverage - this restricts the range of lenses that can be used." was interesting. I've tried using my 75mm Fujinon SWD on the 5x7 in the (vain) hopes the tabled data under-quoted its COA. I have nothing lower. But certainly, if the upper limit is 180 as you say this is a deal killer. I was hoping someone might discuss their experience with this limitation. More weight, less flexibility and, perhaps, another source of light leaks?

Dave - Landscapes
15-Mar-2010, 03:21
Just an update for you on the Canham back with battery - the battery can be changed mid-roll without losing a shot! It uses a standard 9 volt battery. I've used my back in temps as low as -4C and it slowed the wind on operation but was still successful.

The back weighs just over 900g (about 2 pounds).

You can use any lens that has an image circle of around 210mm upwards with confidence. Some lenses of course have more light drop off towards the corners. I use mine with lenses from 90mm f8 Nikon up to 450mm f12.5 C Fuji.

I'll let Paul or others answer the last part of your question.



Paul O
15-Mar-2010, 12:06
I would stick with either the Canham 6x17 or the Shen hao (5x7) 6x17 - don't go down the route of a reducing back with a Shen Hao (5x4) 6x17 - far too fiddly!

If you choose either the Canham or the Shan Hao you will be able to use any lens that covers the 6x17 format as there is no problem with vignetting.

emo supremo
15-Mar-2010, 18:42
Why o why couldn't Ektar have come out this week in 5x7?!