Hardcore modding on a A530, thanks to CHDK!

spectroplasm

Spent the remaining hours I had last night trying to get the proper focal distance of the lens. So far so good, I have a sharp focus on each picture and the focal stepping on the manual lens produce much smoother exposures in both video and picture mode.

My next problems are:
- when taking pictures, the images would be all telecined (has scanlines all over the image), I think this is due to the microshutter I removed on the camera. AF detection still works, face tracking still works fine, but you would get the "shaky cam" icon when taking pictures. and I think this is the reason why the image get's scanlines. Is there a viable remedy to this via scripts or software? previewing the shots before hitting the shoot button is fine, but once the camera has written the image, I get a moire effect on the pictures and when viewing it on PC or the preview and zooming in 100% I see the scanlines. I have attached a before and after lens removal to show what I want to say

- Second theory would be the A2200HD has OIS (floating lens) in between the shutter and ND filter, which is controlled by two hall generators to stabalize in the X and Y axis, upon absence of these motors the camera would get stuck half way and the sensor does the scanlines, I could be wrong but it's a thought.

spectroplasm

I forgot to add that this is only valid for taking pictures, When I take videos it does not exhibit this problem and also I see that in video mode the mechanical shutter of the camera is completely disabled and a CCD electronic shutter is used instead, the swap is very fast and it turn on and off rapidly (albeit following the 60Hz or 50Hz of each NTSC/PAL signal) I was able to verify this by the absence of rolling shutter effect found on most "el cheapo" cameras that use a mechanical shutter and the picture sways in a jello effect when we remove the shutter and shooting a panning video. the A2200HD is so precise it's like the canon 5d2 when comparing video recording coupled with manual M42 lens. Only drawback is that he doesn't do 1080p but only 720p which is a little odd or probably intentional by canon, the A2200HD uses the same DiG!C 4 processor as the 5d2 nonetheless and it's white papers clearly state it's H.264 1080p native and capable (winder if there is a hack or override that would let me use 1080p).

srsa_4c

spectroplasm
- when taking pictures, the images would be all telecined (has scanlines all over the image), I think this is due to the microshutter I removed on the camera.

That's unfortunately right, you need a mechanical shutter to prevent exposure during the CCD's readout phase. Without the mecha shutter, you can only use video mode.
The A2200 has no optical IS hardware.

spectroplasm
Only drawback is that he doesn't do 1080p but only 720p which is a little odd or probably intentional by canon, the A2200HD uses the same DiG!C 4 processor as the 5d2 nonetheless and it's white papers clearly state it's H.264 1080p native and capable (winder if there is a hack or override that would let me use 1080p).

No Canon CCD camera can do 1080p, it's a sensor limitation. In fact, the actual vertical resolution may even be less than the advertised 720p in 16:9 mode.

spectroplasm

ok for the shutter I can make it comeback with a new FPC cable and reroute the trace back to the main PCB, as the microshutter I ripped out wasn't broken nor tortured in any way.
For that video at 1080p, I don't know if we could do the magiclantern trick where we could dump the whole framebuffer before it hit's the oversampler (the compressor that pushes the data to the H.264 codec) of the camera.

Basically ML was able to do RAW video recording using the viewport's input data. the canon 50D had no support for video at all yet with the hack they were able to stream what was on the sensor's raw data directly to the SD slot.
I've read up on it as how it works and on EOS camera's there was a function called lv_rec (or _lcrec I forgot the exact name) what it does is that when the camera is put in liveview the mirror would lock up and whatever the sensor sees it would display it on the LCD for you to see too, what was found was that, even before we hit the record button there was a module that could intercept what was read off the sensor's data and wrote it directly to disk.

The bandwidth was really high and some card's weren't able to keep up with the data, but later on there were possibilities to use crops to isolate the pixel's from the raw data. So instead of writing the whole 16megapixel image (or whatever megapixel the sensor in the camera's were) to disk, you could specify to only crop or take x width and y pixel width and write only that to disk.
The task was easier on the camera as it wasn't a processor hog due to the fact the camera didn't have to recompress the image to it's H.264 codec but just wrote whatever he saw directly to disk. The only limitation was the speed of your card or the speed of the card controller.

spectroplasm

srsa_4c
That's unfortunately right, you need a mechanical shutter to prevent exposure during the CCD's readout phase. Without the mecha shutter, you can only use video mode.
The A2200 has no optical IS hardware.

Thanks for the heads up 😀 I've reassembled the shutter, albeit not in it's original form but I've popped out the magnifying glass part off the whole shutter mechanism and only left in the ND filter and the micro shutter, I've made the orifice larger to accept more light into the CCD and to get rid of that bad vignetting.

So now I've got picture mode back working mint 😀, plus video works well too, all that's left to do is find myself a small corrector lens to straighten the slight fish eye from my 50mm lens setups, and I'm good to go.

will post pictures of all this tomorrow for the curious 😀

srsa_4c

spectroplasm
all that's left to do is find myself a small corrector lens to straighten the slight fish eye from my 50mm lens setups, and I'm good to go.

Before you do that, make sure you look at DNG files, not camera JPEGs.

There are lens-related image corrections in all modern (Canon) P&S cameras.
- Lens distortion correction: depends on zoom, switched off at maximum zoom (tele end), heavily corrected at wide angle. Only applied to JPEGs and camera live view (including videos).

- Vignetting correction: depends on zoom, usually switched off at maximum zoom (tele end), always corrected at wide angle. Applied to live view (& videos), and all still images, including RAW (!).

You can find details in this huge thread.

spectroplasm

Awesome! cool beans.
I'll skim through the link thanks man 😀 hope to get this thing rolling since I'm planing to use it for an upcoming shortfilm project, as I've killed my 5d2 for the moment from a bad MagicLantern build I compiled (my own stupid fault lol)

spectroplasm

Here are some photos of the progress I'm making on the transformation of my small A2200HD into a personnal m42 swappable lens and custom made body, for film work and photography. Enjoy

the custom drilled M42 and M4/3 Lens mount and the project Box.
You can see the Helios 44-2 being tested on the rig

The ongoing project in it's messy state . on your left my trusty feeler gauge and inseparable dremel kit for all my

DIY works.
remade the microshutter and the ND filter component of the camera 😀 now it sits really close to the sensor without vignetting and I can use any m42 lens and close open the iris without vignetting at all.

some of my lens collection for use on this current projetct

spectroplasm

one question to anyone who is working with CHDK scripts, is there anyway I can override the auto-contrasting of the camera? when I shoot a bright area and then move on to a darker are the camera has that nasty auto adaptation of brightness that I would like to override.

Microfunguy

There are a number of disadvantages to using lenses intended for 35mm film cameras on modern small-sensor, digital cameras.

First, you do not have 'normal' focal lengths available.
Your most wide-angle 35mm lens will already be equivalent to the most telephoto on the unmodified camera.

Secondly, in terms of 35mm-equivalent depth-of-field, the aperture is 6x smaller than marked.
In other words, at f2.8 it is already equivalent to f17.
ANY stopping down will result in loss of sharpness due to diffraction.

Thirdly, you are only using approximately 1/36th of the image-circle area that the lens is designed to cover.

David

spectroplasm

Hey David 😀 yes I am aware of the extreme telephoto of the lens on the small sensor, but I'm not concerned with it as the test images I've done are satisfactory to me already 😀 also the shallow depth of field I get with the camera is very pleasing to my eyes.

The only drawback to this is figuring out how to knock that auto contrast the camera does to my images if I move from bright to dark areas in a scene and vice-versa. I'll post a test footage here to show the results so far 😀

this is a demo picture from a Carl Zeiss Jena Biotar 2/58 lens taken at wide open f2, standing distance from subject was a meter away. I'm loving it 😀

srsa_4c

spectroplasm
The only drawback to this is figuring out how to knock that auto contrast the camera does to my images if I move from bright to dark areas in a scene and vice-versa.

If you're talking about video, see the following threads:
https://chdk.setepontos.com/d/5295/1
https://chdk.setepontos.com/d/6113

If the fisheye correction in live view/video starts bothering you, you can use the following Lua commands to switch it off/on:

call_event_proc("Capture.Create") -- needs to be executed only once per session
call_event_proc("LiveImageTool.Dister",<value>) -- <value> is 0 to switch correction off, 1 to switch it on

You need to enable 'Lua native calls' in the CHDK Misc menu for the above to work.

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