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Hi, I've built a MF digital camera from scratch.

T

the scanner-guy

Guest
Ok.. not totally "from scratch" but most of it.
Now I'm near to the completion of the camera, so I thought it can be a good idea to take the project to the attention of this forum, to have some feedback and see if someone has some advice to make it better.



First of all I want you to know, this is not a commercial product, I've built it for myself in my spare time, maybe in the future I'll plan something to earn some money from it, but I have no intention to sell cameras.

Of couse I have not the money to build a large CCD, or even a small one, so I used the components of an Epson scanner (V30) to build a camera similar to the Betterlight scanning back, but medium format, with a live view, quicker, with higher resolution, and first of all, CHEAP. the scanner costs about 90€, and the body and all the machinery inside the camera about 1100€. the lens, from Ebay, 320€
The resolution is the same of the original flatbed scanner, so in the hundreds of MP. I am limited only by the lens and by the scanning time.

The exposure is fixed: I tried to modify the firmware, but it's nearly impossible for me. But I can change the sensitivity using a dimmer connected to the calibration light.
A good scan (like 600dpi, 50MP) can take about 30 seconds, and at 2400dpi takes about two minutes.

I can mount any lens on this camera because I can build any adapter I want, the only problem is the angle of the light on the sensor: I can't use wide angle non-retrofocus lens because causes vignette and color shift (both because of the sensor and the IR-UV filter). I choosed the Beta Variogon 75-150 for this very reason: it's a wonderful lens with a very long focus distance from the sensor, to avoid vignette.

I can provide other information, but I prefer if you ask me what you want to know, because otherwise I'm capable to stay awake all night writing about the camera.

I have no good samples from this camera because I managed to make it work only today. I need a sunny day to test the camera, and I work all week.. maybe next week-end...

SO... what do you think? Is there something that you don't like about the camera? have you some suggestion? Do you know some cheap (under 5-600€)retrofocus lenses(or >70mm non-retrofocus) with very high resolution?

for more pictures visit my flickr gallery

or go to www.projectese.com , but it's under construction, so you will find only information about the early part of the project.

One more thing: I'm not the only one who has built a scanner-camera: in Japan three or four people have their own scanner-camera, with different design from mine.
two of them are YAKU and Takashi Imajo.

Sorry about my bad english, I'm italian, and I don't write in english very often.
 

SergeiR

New member
It an interesting project, but why didnt you go with foldable large format? It would give you more space to play.. And easier scanning too.
 

Graham Mitchell

New member
Your English is very good and this is a really interesting project. It might not be the first scanner camera I've seen but it looks to be the best built. I look forward to seeing some images.
 

emr

Member
I don't know what to ask, but this is a very interesting project and I'm certainly waiting to hear more of it. Well done!
 
T

the scanner-guy

Guest
thank you all for your kind words :)

It an interesting project, but why didnt you go with foldable large format? It would give you more space to play.. And easier scanning too.
If you watch the flickr gallery, you'll see that in the early stage of the project it was a large format camera. But the problem is the size of the sensor. The CCD from the Epson V30 is about 42mm long. All the ccd scanners have a mirror box to simulate a longer distance from the glass.

so removing this mirror box, the scanner generates an anamorphic image.

It's usable in this way, like a very, VERY large panoramic camera:



...but there are some issues with the software: the color channels are phisically shifted to left and right, and after the realignment some artifacts are visible in the high contrast zones.
Watch this picture for example:

you can see what I'm talking about.

And if I want to take a bigger picture I had to stitch multiple images, which with a self made ultra-large-format camera (with no ground glass or precise focus scales) is not that easy.

Here's a video from when it was a large format camera:
http://www.youtube.com/watch?v=3jrm3aNDRqg


The only way to solve these issues is to reduce the travel of the sensor to archieve the same aspect ratio of the original scanner, so now it's 42x59mm.
Here's another video, where you can see the new tranmission working:
http://www.youtube.com/watch?v=bTsT42bCS6o

Btw, I had no problem using batteries but probably I'll need to make a new battery housing because 12v is too low, and I have no space inside the body for a 14,4v battery...

so.. anyone has some advice for a new lens?
 
T

the scanner-guy

Guest
thank you all for your kind words :)

It an interesting project, but why didnt you go with foldable large format? It would give you more space to play.. And easier scanning too.
If you watch the flickr gallery, you'll see that in the early stage of the project it was a large format camera. But the problem is the size of the sensor. The CCD from the Epson V30 is about 42mm long. All the ccd scanners have a mirror box to simulate a longer distance from the glass.

so removing this mirror box, the scanner generates an anamorphic image.

It's usable in this way, like a very, VERY large panoramic camera:



...but there are some issues with the software: the color channels are phisically shifted to left and right, and after the realignment some artifacts are visible in the high contrast zones.
Watch this picture for example:

you can see what I'm talking about.

And if I want to take a bigger picture I had to stitch multiple images, which with a self made ultra-large-format camera (with no ground glass or precise focus scales) is not that easy.

Here's a video from when it was a large format camera:
http://www.youtube.com/watch?v=3jrm3aNDRqg


The only way to solve these issues is to reduce the travel of the sensor to archieve the same aspect ratio of the original scanner, so now it's 42x59mm.
Here's another video, where you can see the new tranmission working:
http://www.youtube.com/watch?v=bTsT42bCS6o

Btw, I had no problem using batteries but probably I'll need to make a new battery housing because 12v is too low, and I have no space inside the body for a 14,4v battery...

so.. anyone has some advice for a new lens?
 

archivue

Active member
apo sironar digital lenses such as the 90 can be bought sometimes on ebay for a good price, and they are stellar performers !
 
T

the scanner-guy

Guest
The sironar-digital 90mm seems a good choice. I found one on Ebay below 500€.
With the precision I need it will be impossible to use an helicoid to focus, at least not those chinese ones on ebay(I can build a good one, but it can be very expensive), and I'm tired of bellows.. so the logical conclusion would be a simple long screw mount with a ring-nut to block the whole thing when I find the focus... I need to think about it.

Anyway right now I'm doing some tests to find issues and things to improve.
This shot is about 1/9 of the entire image (like the central square in the rule of thirds).



As you can see the channels are not aligned all along the image. This is because the motion is not costant enough (not a big deal: it's only a matter of changing the transmission belt in this case).
I'm using an old spare sensor, and in these testing sessions I don't care too much about cleaning the sensor every time I open the camera, so the dust particles create some horizontal lines in the image.
To have the best performance the camera needs to be as cool as possible. After every full-scan and preview-scan the sensor gets really hot and some noise begins to be visible in the image, starting from the blue channel.

To give an idea of the sensitivity of this camera, this was done at about f/6.8 with a 500W lamp at about 25" from the subject (the lamp was visible in the full image). Considering an exposure time per line of about 1/250 multiplied by 2 because it's a 6 lines sensor, it's something between ISO 200 and 400. This is the maximum sensitivity of this camera. I don't know the minimum but I assume it's well below ISO 100.

Now it's difficult to focusing, because I didn't mount the live view yet, so I have to take a lot of preview and zoom scans, moving the focusing ring, but the preview resolution is not enough to ensure the perfect focusing: I tought I focused on the 50€, but as you can see, the focal plane is on the shutter cable.

I'm uploading a video on youtube, made during the taking of this picture so you'll se the procedure in detail.

By the way, I can mount 35mm format lenses (they only have to be not too close to the lens), so if you have some advice on some high resolution lens under 5-600€ it would be appreciated(one of the advantages of having a such high resolution and scalable sensor is to scan at very high resolution only a crop of the entire image).
 

SergeiR

New member
Hm. I see what you saying about scanning back on foldables. Thanks for illustrating point,
and yeah, after i asked - i went to check flickr gallery ;)

Need to get some cheapo scanner taken apart, i guess, so i can be on same page. Right now i am basically just coming from thinking "well you know.. you can basically snap scanner on the back of foldable's groundglass replacement and be generally happy" :)))
 
T

the scanner-guy

Guest
You can do it: you only have to disable the light from the scanner.
The only problem is the grain of the ground glass: no matter how fine it is, the picture will look too grainy. I've tried it(the very first image in my flickr gallery), but I didn't like it at all.
If you don't want then to use the ground glass there are two ways: one is to use a modified CIS-sensor scanner (the cheapest on the market) and use it as a black and white large format scanning back(high resolution but poor quality). The other way is to use a CCD scanner(like I did), with the small sensor, and all the issues that it takes... but the result is waaaaay better.
 
T

the scanner-guy

Guest
Today I was calibrating the lens to find the infinite focus, and I did a comparison between the scanner and my DSLR (Sony A55).
Also, I found some issues going over 1200dpi, I can say this is the maximum resolution I can get by now.






Both shots done at f8 and with matching field of view (75mm for the scanner, 35mm for the DSLR). The CCD wasn't clean (I need to open the camera a lot of times to calibrate the lens) so you'll notice some horizontal stripes and lines in the scanner's picture.

Anyway, a 143MP (1200dpi) 48bit file is about 800MB. Even if it was possible to go up to 4800dpi, I don't have like 30GB of RAM to use the file...
 
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