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CHDK on SD4000/IXUS 300 HS

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Re: CHDK on SD4000/IXUS 300 HS
« Reply #70 on: 04 / September / 2017, 16:03:02 »
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Turns into a monologue, but I hope these tips will be useful to someone...

Here's a good low-light compromise: 35mm f2.8 ISO 800. This extends the sharp "in-focus" range from meager 2 meters to somewhere between 4-8m. Everything is a bit sharper. 35mm is still wide, IS is effective, and f2.8 gathers a lot of light. There is more detail at 100%, so this seems to be pretty good solution for indoor shooting, if you can't use 50mm f4 for various reasons but still need some 100% detail. In fact, on desktop monitor everything looks pretty good (unless you're viewing 32 inch screen from 1 feet distance).

Outdoor, with distant objects, one can only hope there will be sufficient light for 50mm f4, or greater. I took a sharp shot at 106mm and 1/5s wide-open, in the middle of the night, which means that IS is much more effective at longer focal lengths. IS is a bit unpredictable, though. Some 35mm shots were blurred at 1/13s, but some 35mm shots were sharp at 1/5s. The only certainty is that at f2 nothing helps with getting distant objects sharp, stabilization, focus, low ISO, fast shutter, absolutely nothing - only contrasty areas and good composition/processing can "save" your image. At 28mm, avoid apertures below f7.1 if you want to print large. At DPReview they concluded, SD4000 is not for large prints. But with CHDK and 50mm f4 you CAN do large prints. So, there are workarounds, maybe not for every situation, but for most realistic shooting scenarios.

If one needs startup script with set_zoom to 35mm, the value is 6. Also, RAW shooting is mandatory for getting decent IQ at high ISOs.

Setting up & learning this camera was really fun, an interesting and "unique" experience. :)

I put all this effort simply because this is the photographic tool I can have anywhere, anytime with me!

Re: CHDK on SD4000/IXUS 300 HS
« Reply #71 on: 04 / September / 2017, 17:13:21 »
Turns into a monologue, but I hope these tips will be useful to someone...
How is the rewrite of the CHDK User Manual Custom Auto ISO feature going?  8)
Ported : A1200  SD940  G10  Powershot N  G16*

Re: CHDK on SD4000/IXUS 300 HS
« Reply #72 on: 07 / September / 2017, 17:29:51 »
Turns into a monologue, but I hope these tips will be useful to someone...
How is the rewrite of the CHDK User Manual Custom Auto ISO feature going?  8)

Well, I have to spend more time with the camera... Maybe then I could do it...

The "35 2.8" solution is great, it made this thing a couple of more times useful in low light. Sure, f2 looks decent indoors in desktop monitor size or smaller, and it gives us faster shutter speeds when needed, but I actually used 35 2.8 outdoors during night, for still subjects, and was blown away with results. It's like a different cam zoomed in and stopped down just a little bit. Of course, the strong contrast produced by artificial lighting adds to the sharpness, but this looks pretty good even at 100%. Earlier, I was trying 28mm f4 ISO 1600 but that's not very effective. 35 2.8 ISO 800 does the job: you lose less than 1 stop of light, however, when you zoom in on your subject you often gather a bit more light + image stabilization is INSANE at 35mm, better than 28mm or 50mm. I took a shot almost in moonlight, there were a couple of lamps but small and weak - it was 35mm f2.8 ISO 3200 at 1/3s. And it was sharp enough. Hell, there were no signs of handshake blur. This is the new record for me, with Nikon 18-55 VR II I was able to get down to 1/5s hand-held, but 1/3s? How awesome is that? I was also able to restore and pull up the natural colors in post. I mean, this is just unbelievable for such a small pocket camera. All made possible with CHDK RAW, because JPEG at ISO 3200 looks like [admin: avoid swearing please].

So, it's mostly 50mm f4 in daylight and 35mm f2.8 in low light. If you don't want to mess with aperture, f7.1 gives decent results at all focal lengths. Furthermore, noise looks pretty good, the pattern is natural, similar to S95. If you go for "softer" look, you just leave the noise & sharpening as it is and it will look fine even in large prints.

I had a Lumix LX7 in very good condition for like $130 and didn't buy it. It's a good camera but comes in annoying size. If I'm going to carry a bag, I'll bring my DSLR. The little SD4000 turned out even better than I anticipated :D

But this tool is NOT for Program & Auto shooters, particularly those who just turn on the camera and shoot at 28mm. They might be unhappy with the results and blame it on the camera, without even realizing its true potential...

Re: CHDK on SD4000/IXUS 300 HS
« Reply #73 on: 11 / October / 2017, 16:43:35 »
One more thing...

There are definitely some issues with lens elements movement / aperture. For example, if I use start up script to set 35mm f/2.8 from f/2, image will be very sharp. However, if I zoom in longer than 35mm and then zoom out to 35mm f/2.8, the image will not be as sharp. Also, it seems that if you shut down camera at smaller aperture such as f/4 or f/7.1, there could be even more softness when going back to 35 f/2.8.

1) I get best results when I shut down camera at f/2, and then power on to 35 f/2.8.
2) Second best option is to shut down wide-open and then power on to 35 f/2.8.
3) I get worst results if I shoot 50mm f/4 or 106mm f/7.1, then zoom out to 35mm and set f/2.8.

I even thought that softness at f/2 might have something to do with this, but I've never managed to get a really sharp shot at the widest aperture. Option 1 produces the sharpest shots in low-light, it's the best way to shoot this thing in dark conditions. It's like a 35 f/2.8 prime then.

I believe this has nothing to do with CHDK, it's most probably some kind of lens design fault. It's difficult to notice as well! The problem is non existent when switching between 50mm and long end, for example, but zooming out to 35mm wide-open introduces the problem. It happens with or without start up scripts. Everything seems to be pretty good at f/7.1 (which is also surprising).

Maybe it's just my copy? Is this possible with a compact/retracting lens?
I suppose it's just a side effect of having real aperture in such a tiny lens.
« Last Edit: 11 / October / 2017, 16:46:32 by Robert1975 »


Re: CHDK on SD4000/IXUS 300 HS
« Reply #74 on: 12 / October / 2017, 00:20:29 »
One more thing...
I just have to say,  you are probably getting more out of this camera than anyone, including the original Canon engineers, ever intended or thought possible. It's nice CHDK added a few capabilities that helped with that.
Ported : A1200  SD940  G10  Powershot N  G16*

 

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