Increasing camera low light and range performance

[Wayne Morellini]

Hi

I am looking at buying a cheap consumer camera. Does any body know of a way to increase their low light performance and the light range it can work over (at set aperture and gain)?

I've looked at the MX500 (953) for instance, at low light is an underexposed mess, and you just can't have a external window view in proper exposure at the same time, unlike professional models, so it is a bit useless.

I don't know enough about optics but I was thinking that an attachable lenses assembly with 4 times + the lense surface area will collect four times more light, and increase the low light capability by at least double. I am also wondering if there is a method/filter out there that will increase the light range by directly passing dim light and progressively dimming bright light, so as not to under expose or overexpose the CCD?

Would anybody be able to help?

By the way, does anybody know of any home made professional camera projects out there (like www.pixelmonger.com did)?


Thanks.

Wayne.

[Rob Lohman]

I'm not sure what you are looking for exactly, but not even
professional cameras usually have such a latitude. What they
do is:

- use a gradient filter so you can bring down a part of the image
- add extra light to the room to also lower the contrast
- put nd (neutral density) on the window
- add a silk or other equipment outside to cut the light that comes in through the window

Also you cannot use a lens with a larger surface because your
CCD chips have a fixed surface. If the light levels are too low,
add light!

[Joseph George]

If you want a better performance, just get a better camera. For a wider exposure range -- get one with larger chipset and ND filter(s) built in.

[Wayne Morellini]

Thanks Robin and Joseph for your help

I wanted to aviode buying a very expensive professional camera or lots of extra lighting. My reasoning was that you could focus a larger lense on the same CCD area. Maybe a better camera like the JVC GY DV 5000 will be reduced to a cheap enough price eventually.

Thanks

Wayne

[Vladimir Koifman]

Many wide angle convertors improve low-light sensitivity somewhat.
I'm not sure if one can improve it by four times, but I've seen about a half-stop improvement.
Basically, convertor might increase the effective aperture. Not all of them do, but some.
In any case, the improvement I've seen was not that big to compensate for serious low-light deficiency of some cameras.

Vladimir.

[Yow Cheong Hoe]

Wide angle lenses do seems to add a little light, as the front of the lenses are generally much wider. However, the WA lenses themselves are not perfect, being made of glass, and it'll absorb a little light.

I use the Fujifilm 0.79x WA (meant for the Fujifilm Finepix S602Zoom Digital Camera) on my MX350. Good results and unnoticeable vignetting. The scenes with or without the WA has some difference in lighting, but it's probably just in the range of + or - 1db (in digital gain mode).

[Vladimir Koifman]

I've seen more than 1db improvement. May be as much as 3-4db. The converter I tried was x0.5-0.6. I dont remember its brand, it was some 5 years ago.
In any case, if it makes 15 Lux camcorder capable to shoot at 10 Lux, it's not that big deal.

[Peter Jefferson]

one more thing i dont think has been mentioned ....

One thing ive come across when doing alot of "repairs" is that alot of videogrpahers arent using the backlight compensation of the camera.

most cams these days have a backlight compo featrue.. not many people use it...


under the stabilizer button, theres a backlight compo button.. mess around with it.. it might help...

[Wayne Morellini]

<<<-- Originally posted by Vladimir Koifman : I've seen more than 1db improvement. May be as much as 3-4db. The converter I tried was x0.5-0.6. I dont remember its brand, it was some 5 years ago.
In any case, if it makes 15 Lux camcorder capable to shoot at 10 Lux, it's not that big deal. -->>>


Thanks Vladimir, this sounds fantastic, imagine what it would do to a VX2000?

I'm curiouse though, when they say that the JVC HD10 is 35 Lux and the Panasonic 953 is 15 Lux, is that before gain and lolux mode or after?

I have been told that trying to put an attachement on the lense ruins the optical design (like the JVC DV 3000 is designed to make diferent colours focus at the same distance, instead of using three chips). Does the lense have to be specially designed for the camera?

I have heard of adaptors to attach bigger 35MM lenses to a camcorder, does anybody know of any of these?


Thanks

Wayne.

[Wayne Morellini]

By the way. Thanks Yow and Peter for your help.


Peter, thanks for the suggestion, I do intend to use the backlight compensation feature, but it makes the outside go completely overexposed. I was hoping some genuise would have figured out a light sensitive filter designed to progressively dim brighter light. It would help "crippled" cameras a lot, along with increased apeture.

Thanks

Wayne.

[Vladimir Koifman]

Wayne, a compressed dynamic range is the "backlight cure" that some CMOS sensors manufacturers offer. For instance, see this:

http://www.smalcamera.com/technology.html

This solves backlight problem, sort of. However, the resulting image looks flat and lacks "punch" of linear CCD camera.

I'd like to see some brave manufacturer delegates to us control over compression ratio. So we could optimize it for our tastes.
Even gamma control in one form or another would be nice.

[Wayne Morellini]

Dear Vladimir

This is more like it, I have seen a near $20000AU Sony Camera that would do something like this.

I see some wash out there, but, in the example picture, if they matained the same brightness for inside and gave more range to the outside, instead of brightening all of it the picture would be a lot better. You should check out the page on there altrawide 3000 security model (1920*480 pixels), wow you could do a cheap 2.35:1 ration film ;), joking, there probably is a lot of quality isues still to be worked out, but amazing. What I was suggesting would get even better results than this (and closer to film). As you can see if I was to film a scene like this I would have to add so much in store lighting or window tint on the window as to make it very awkward.

http://www.smalcamera.com/w3000wide.html

With 100 Meter firewire, you think they could make a camera with 720p firewire output.

Thanks Vladimir, that was really great.

<<<-- Originally posted by Vladimir Koifman :
I'd like to see some brave manufacturer delegates to us control over compression ratio. So we could optimize it for our tastes.
Even gamma control in one form or another would be nice. -->>>

Yeah, DVCPRO50 tape would be good with it aswell. They will probably have to change the codec standard to support it though. Gama control would be good for the cheap cameras.

I read, a few years ago, that MiniDV could go upto 10 (maybe 100, I forget) times more capacity, the technique was already developed, so JVC gives us HD25 MinDV instead. Also the DVCPRO tape is also developed to give playback many more times than MiniDV that degrades after 7-12 times play/record.

Thanks for the help

Wayne

[Peter Jefferson]

final thought.. feel like jerry springer now.. LOL

the old fashioned way to remove shadows and backlighting issues during daylight is to use a light...
A small 50 to 100w should be sufficient for close shots.... anything up to about 10 metres..

[Joseph George]

You can also use a large reflector to fill the shadows.

As to low lux rating of a camera, it is always with gain up.

[Frank Granovski]

"As to low lux rating of a camera, it is always with gain up."

Or, shoot in more light.