A quick report. Ive just modded the 40D, and it still works .
A couple of big supprises.
It easier to mod than the 300D, less fiddly. It took 1.5hrs all up, no drama at all. The instructions wernt quiet a comprehensive as for the 300D, but the ommisions were fairly obvious.
The second supprise was, it still auto focuses, even without a replacement glass . It appears focus still works on the shaker glass, which was 1st in the sandwich.
If any one has modded a 300/350D, dont heasitate to give the 40D a try, its easier.
Congrats Fred! Seems like everyone has a modded 40D these days.
I had a look at the instructions on how the mod a DSLR camera. The steps seemed pretty involved so for a newbie who is about to get a DSLR. I think I will stay away from modding it for awhile.
Looking forward for your first light with the mod.
You can see on the attached graphs for the 350D, the filter glass cuts off Ha (6500) and SII (6720) severly, but the filter removal, despite improved Ha, SII response, has nasty response bumps after 7000. The front filter (I dont have a graph) smooths these out to give natural response with an extended red curve. I dont know if the standard in cam white balance is still valid, but it would be close.
LOL Mike, not this time me thinks, the 40D is much easier to use as it is, with just one USB cable hanging out of it. And BTW, the live preview for focus, preview image with tweakable histogram on exposure complete and USB bulb is a killer, this cam is a snack for astro, a huge step up from the previous models, very impressive. Attempting a 1st light as we speak, Murphy has gone holiday this week, the sky is dark .
nice one Fred, did you take any pics of you doing the mod? i might actually be interested in another 40D mod tutorial. I'm quite surprised that you can still use the autofocus without any filters at all?
Also, do you think if you can post a AWB and a CWB shot of trees/sky? just want to see some comparison with mine as im having a few issues with balancing my colours.
Phil, Eric. Im just imaging now, Im dead wrong on cam-set white balance, its as red as hell of course, on reflection it makes sense with the extended red response. This is all mute, as you just rebalance in PS. I hope you are imaging with RAW now Eric, or Ill rip your arms off , its not hard, you just convert with the Canon app to TIFF before IP/PS. Standard white balance is applied to JPEGS so that will be crap, but not to RAW. White balance is irallevent anyway now, its a no brainer in PS.
Its been a long time since I used a DSLR, so its relearning on the fly .
OK Eric, Ill do some terestial shots tomorrow for you. BTW, I noticed a slight colour tinge on the dust-shake glass, I hope there is not any filtering done on it
I suspect the dust-shake glass is sitting on top of the distorted neoprene seal/adheasive left after the filter removal (thats the one negative thing that happened, the filter broke, but I dont care), hard up against the glass stack retaining clip by pure luck. I understand focus has something to do with the top glass layer (which seems to explain why it still works, despite the filter removal, I guess if I had done it properly, the shake glass would have been sitting lower), although I dont know why, I thought auto focus relied on optical artifact edge transition difference, cant see the importance of the glass its self.
No, I didnt take pics of the mod Eric, why would you need it, yours is done ;-).
Eric. Ive read the thread you posted, and it seems youve gone into it much more than I have. I dont need to as I will only use it for Astro pics.
From what Ive seen elsewhere, the UV/IR blocking filter fitted as a mod allows extended red (into IR) response and just cuts off the nasty curve spikes after that, which all affects AWB for daytime use. Thats why another front daylight filter is required to bring balance back to normal for terestial use. It seems you have discovered that already. The thread also discusses other issues Im not aware of, it seems really you are the IIS DSLR expert Eric .
Hi Fred, thanks for the image. Try leaving the dial in AV mode and use AWB . Thats very odd your camera. Since the original filter has been fully taken out, the IR and UV spectrum will become unblocked. If the IR spectrum becomes unblocked, your camera should be more redder than that and the green colours on the leaves will also become red due to the IR light unless you are taking the pic with a UV/IR blocking filter infront of the lense?
According to a report by Christian Buil, the front glass on the 40d has basic UV/IR filter properties. Check the before/after response curves in fig.6 on his website http://www.astrosurf.com/buil/eos40d2/filter.htm
It seems you can almost get away without a UV/IR filter although adding one would give you tighter stars.
Yes... I'm looking at doing the same as Fred, simply remove the filter glass, keep the front glass and transform the 40d into a dedicated astro camera. Keep my 400d for daylight.
Damb, damb, damb I just looked at the Christian Buil site again, I didnt study it properly last time I saw it, and just went by the instructions. There are 3 filter layers altogether, I only removed one .
Well, ill pull it apart again and have another go, and read christians site again, thanks Eric and Rob for your inputs.
Eric, Ive done some checking. Attached is a modded 350D pic with no filters at all (for sure), a modded 350D pic with a Astronomik Profi L type 2c screw-on-the-lens filter (UV/IR block) and a modded 40D pic with filter 2 removed but the shaker glass filter 1 still in place (as per Christians page). The 350D with lens filter and 40D pics look very similar, which as Rob says means the shaker glass filter is acting as the UV/IR cutoff filter as per Christians response graph. ie, I dont really need the Astronomic lens filter for my 40D, as christian also points out (I translated the page).
The 350D no filter pic matches the very reddish pic you posted in another thread, which tells me your 40D has had both filters 1 and 2 removed (which means your shaker glass is out or has also been replaced with clear glass) and you would need UV/IR blocker for Astro and a daylight filter for terestial.
From what I understand, no filter at all in your cam is no good for astro due to nasty response spikes in IR swamping images with IR. Although this means you can do IR photography . Perhaps by mistake clear glass was inserted, have you done any astro picks with it?
Christians page seems to have an error, on fig 1 I think the "phaser layer" should be "filter 2", fig 4 and 5 would then make sense, and because "phaser layer" is not mentioned anywhere else on the page or on the graphs. The "low pass" filter would be for UV I guess and not need removal.
I maybe wrong about all of this, but I am sure I removed filter 2 which means it should be OK the way it is. I also hope the Astronomik Profi L type 2c filter I got is the right one. And I do think that you have clear glass (no filters).
Hi Fred, yes I think you've done the right thing. As far as I can tell you've removed the visual light filter, the one in the middle. )You won't need to disassemble your camera again!) The filter on the front, attached to the dust shaker, seems to be a gentle UV/IR filter, according to Christian's report a more aggressive external UV/IR filter may still be required to get pinpoint stars. I can't wait to see your results under a dark sky!
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, less fiddly. It took 1.5hrs all up, no drama at all. The instructions wernt quiet a comprehensive as for the 300D, but the ommisions were fairly obvious.
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