Gain numbers for ASI120MC-S and ASI120MM-S?

sanderp

Hi,

I'm considering one of your USB3 cameras to replace my QHY5L-IIc. One of my concerns is that so far I have been unable to get gain numbers for the '5. There is also some weird business where increasing gain does not result in increasing ADUs but has dips. In any case, this is not about the '5, I'm just trying to explain why I am trying to be thorough before handing over my money again :)

One more question, does the 120-S series support the guide port in 12b readout mode? The '5 does not I just discovered.

My goal is planetary imaging, I have an HD1100 and just got a 2.5x Powermate. If you think the '174 is a better match let me know. I'll want to know its gain numbers too then.

I intend to use FireCapture.

Thanks!

Sander

riklaunim

IMX174 has some advantages over Micron/Aptina sensors like nearly no fixed pattern noise. I have ASI120MM and the gain slider works like normal.

sanderp

Thanks for your reply. Good to know the 120MM gain works as expected. Looks like Sony managed to put their CCD magic on CMOS as well.

Sam@ZWO

there is such limit with the ASI120 USB2.0 camera the guider port won't work when enable 16bit output

ASI120S or ASI174 is better for you

sanderp

Thanks, that is good to know. I would get the USB3 version for sure even if ST4 was supported in USB2.

If the cameras cost the same would you still recommend the 174 for planetary work or is the difference between the two limited once you use ROI on the 174 to reduce the field?

I would still want to see gain figures for either camera though :) How many e per ADU for several gain settings in FireCapture?

sanderp

Hi again,

I'm still hoping to hear gain numbers for these two cameras. Before my next camera purchase I need to have clarity on that otherwise it is too much voodoo. I'd rather not go through the somewhat painful process of determining gain myself. It's not secret, right?

Thanks,

Sander

riklaunim

Usually its up to 24dB or more depending on model. And it's not a fixed gain like in DS cameras.

Sam@ZWO

the gain range of ASI174 is 0-40db (0-400)

24db anlog gain and 16db dital gain

the Gain is 0.49 e/ADU (16bit)

ASI120 work like this:

gain range 0-100

0-16

analog gain 1x

digital gain 1-2x

16-32

analog gain 2x

digital gain 1-2x

32-48

analog gain 4x

digital gain 1-2x

48-64

analog gain 8x

digital gain 1-2x

64-80

analog gain 8x

digital gain 2-4x

80-100

analog gain 8x

digital gain 4-8x

the Gain is 0.21 e/ADU (16bit)

sanderp

riklaunim wrote:
And it's not a fixed gain like in DS cameras.

That is interesting. Can you elaborate on that a little? Did you mean to say 'you adjust the gain depending on the situation' (which you've told me before) or is gain adjusted under the covers by the camera or driver?

Thank you!

Sander

sanderp

Thanks Sam for the detailed reply. Let me digest and follow up later if you don't mind. I *really* appreciate your active participation. Key to deciding which camera to buy.

Sander

riklaunim

For lunar/solar imaging I can use lowest gain possible and short exposure as the object is very bright. For Mars more gain is needed to retain fast framerate, for Jupiter bit more... for very dim Saturn some channels need all the gain camera has to get like 30 FPS with good image quality (histogram fill etc.). With planets it's not possible to use more than 8 bit of dynamic range. For lunar/solar sometimes there may be a chance that more than 8-bit can be really used.

sanderp

Thanks that is very helpful.