some tests on my NV-MX500EG

Mattia Visintini · February 13th, 2004, 09:42 AM

Guy,
regarding you search for the ASA sensitivity, what value did you find?
Comparing it with my nikon reflex camera, i found it out to be around 50 ASA.... but i am not really sure about the method....
i have a 300mm f4 fixed telephoto lens, so i pointed my mx500 to a fairly uniform overcast sky with an equivalent amount of zoom, setting the shutter priority to 1/50 and finding a spot where the aperture would go to f4.
Then i took the nikon, set it at f4, aimed it a at the same point and then changed the ASA settings until the AE program gave me a shutter time of 1/60 (which anyway is less than 1/4 of f-stop difference from 1/50).
...in theory it should be correct (approximately).

not strictly on topic, but does anyone know the dynamic range which can be captured in a shot? I mean the f-stop difference between the darkest, and lightest discernible detail?
I'd like to do some tests on it, but i need to find a decent light meter first...

Guy Bruner · February 13th, 2004, 09:52 AM

Mattia,
Interesting that you took the same approach to identify ASA!! However, I did this a little differently.

I used my AE1 Program with its F1.8 50mm lens because I wanted the two lenses to be roughly equivalent (the 953 is F1.7 in video). Then, I basically used the same approach. I set the shutter to Auto (1/60), pointed the 953 at a light source that completely illuminated the CCD, then shifted to manual and checked the iris. Then, I set the Canon to 1/60 shutter, pointed at the same light source and adjusted ASA until the iris was roughly the same. I get between 100 and 200 ASA with this, but want to repeat the tests a few more times at different light levels to validate.

Guy Bruner · February 13th, 2004, 10:27 AM

Ok,
I have redone my ASA tests in indirect natural light using off white backgrounds (nonglossy). I measured one background at F8, 1/60 (both cameras)...this resulted in ASA80 on the Canon AE1 Program. The second background was at F2.0, 1/60 on both cameras...this also resulted in ASA80 on the Canon. BTW, this was done with no filter or lens shade on the DV953.

I have to conclude that the DV953 has a light sensitivity similar to ASA80 film.

Mattia Visintini · February 13th, 2004, 11:22 AM

Thanks for the results Guy!
I also repeated the test a couple of times, this time also with a 20mm f2.8, and the results are similar to yours.... in my case they oscillate between 64 and 80 ASA.
Anyway to be really sure I will do them again with a professional light meter a friend of mine has, as soon as possible (unfortunately he's away). Then i'll also try to find out what f-stop range the ccd's can capture.... it's something i'm quite interested in.

Guy Bruner · February 13th, 2004, 11:29 AM

Mattia,
A good light meter in incident mode would be a more accurate check. But, I believe we can safely say the sensitivity is approximately ASA80.

As an aside, in Gain Up mode, each 6 dB is equivalent to doubling the ASA rating at 1/60 shutter, IIRC. So, +6 dB would be ASA160, +12 -- ASA320, and +18 -- ASA640. I'd say the 953/500 is pretty sensitive in low light.

February 13th, 2004, 09:42 AM	#16
Mattia Visintini New Boot Join Date: Feb 2004 Location: Trieste, ITALY Posts: 8	Guy, regarding you search for the ASA sensitivity, what value did you find? Comparing it with my nikon reflex camera, i found it out to be around 50 ASA.... but i am not really sure about the method.... i have a 300mm f4 fixed telephoto lens, so i pointed my mx500 to a fairly uniform overcast sky with an equivalent amount of zoom, setting the shutter priority to 1/50 and finding a spot where the aperture would go to f4. Then i took the nikon, set it at f4, aimed it a at the same point and then changed the ASA settings until the AE program gave me a shutter time of 1/60 (which anyway is less than 1/4 of f-stop difference from 1/50). ...in theory it should be correct (approximately). not strictly on topic, but does anyone know the dynamic range which can be captured in a shot? I mean the f-stop difference between the darkest, and lightest discernible detail? I'd like to do some tests on it, but i need to find a decent light meter first...

February 13th, 2004, 09:52 AM	#17
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Mattia, Interesting that you took the same approach to identify ASA!! However, I did this a little differently. I used my AE1 Program with its F1.8 50mm lens because I wanted the two lenses to be roughly equivalent (the 953 is F1.7 in video). Then, I basically used the same approach. I set the shutter to Auto (1/60), pointed the 953 at a light source that completely illuminated the CCD, then shifted to manual and checked the iris. Then, I set the Canon to 1/60 shutter, pointed at the same light source and adjusted ASA until the iris was roughly the same. I get between 100 and 200 ASA with this, but want to repeat the tests a few more times at different light levels to validate.

February 13th, 2004, 10:27 AM	#18
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Ok, I have redone my ASA tests in indirect natural light using off white backgrounds (nonglossy). I measured one background at F8, 1/60 (both cameras)...this resulted in ASA80 on the Canon AE1 Program. The second background was at F2.0, 1/60 on both cameras...this also resulted in ASA80 on the Canon. BTW, this was done with no filter or lens shade on the DV953. I have to conclude that the DV953 has a light sensitivity similar to ASA80 film.

February 13th, 2004, 11:22 AM	#19
Mattia Visintini New Boot Join Date: Feb 2004 Location: Trieste, ITALY Posts: 8	Thanks for the results Guy! I also repeated the test a couple of times, this time also with a 20mm f2.8, and the results are similar to yours.... in my case they oscillate between 64 and 80 ASA. Anyway to be really sure I will do them again with a professional light meter a friend of mine has, as soon as possible (unfortunately he's away). Then i'll also try to find out what f-stop range the ccd's can capture.... it's something i'm quite interested in.

February 13th, 2004, 11:29 AM	#20
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Mattia, A good light meter in incident mode would be a more accurate check. But, I believe we can safely say the sensitivity is approximately ASA80. As an aside, in Gain Up mode, each 6 dB is equivalent to doubling the ASA rating at 1/60 shutter, IIRC. So, +6 dB would be ASA160, +12 -- ASA320, and +18 -- ASA640. I'd say the 953/500 is pretty sensitive in low light.