Camera gain settings in ASCOM v Gain Settings in other software.

[centroid]

I have a 294c based camera, which I am controlling via the ASCOM interface within Astroart 8.

I understand that the unity gain setting for this camera circa 117, however within the ASCOM interface, the gain setting goes from 0 to 100.

I'm told that in order correlate the ASCOM gain setting numbers with those used in other software,  it is necessary to multiply the ASCOM gain number by a factor of 10.

For example, a gain setting of 10, on the ASCOM scale, is equal to 100 in other software.

Is this correct?

[vlaiv]

1 hour ago, centroid said:

I understand that the unity gain setting for this camera circa 117,

This is true only for ZWO camera with that sensor. Other vendors can and will use different gain to e/ADU mapping.

Try looking up their respective documentation to see what actual gain value is.

Altair for example has this table on their website (its only an image so a bit hard to read):

I'm not sure what Gain vs Relative Gain vs Rel Gain (db) is.

Maybe there is relationship between ZWO version which uses 0.1db units so 117 is 11.7db, and in above table we see that it does correspond to Relative gain of 3.96 / Gain of 400 and e/ADU of 0.98 (11.96db that is).

Not sure which value is entered in ASCOM driver - probably Rel Gain in db units so 11.7 would be unity - if you can enter decimal values.

[centroid]

14 hours ago, vlaiv said:

This is true only for ZWO camera with that sensor. Other vendors can and will use different gain to e/ADU mapping.

Try looking up their respective documentation to see what actual gain value is.

Altair for example has this table on their website (its only an image so a bit hard to read):

I'm not sure what Gain vs Relative Gain vs Rel Gain (db) is.

Maybe there is relationship between ZWO version which uses 0.1db units so 117 is 11.7db, and in above table we see that it does correspond to Relative gain of 3.96 / Gain of 400 and e/ADU of 0.98 (11.96db that is).

Not sure which value is entered in ASCOM driver - probably Rel Gain in db units so 11.7 would be unity - if you can enter decimal values.

Thanks for that input Valaiv.  I think the ZWO and Altair cameras are identical, and probably made in the same factory, Same case, different colour 🙂

Within the ASCOM interface, the gain settings do increase in decimal steps, so that probably confirms the factor of 10 figure that I was quoted. A Logarithmic scale, which makes sense.

[vlaiv]

5 minutes ago, centroid said:

I think the ZWO and Altair cameras are identical, and probably made in the same factory, Same case, different colour

Not sure about that ...

vs

 

[FLO]

3 hours ago, centroid said:

I think the ZWO and Altair cameras are identical, and probably made in the same factory, Same case, different colour 🙂

No. They are not.

I don't know where this myth started but it is most definitely not true. 

ZWO cameras are designed and manufactured by ZWO. 

Altair cameras are designed and manufactured by ToupTek in China.

ToupTek is essentially an OEM manufacturer (a company that designs and manufactures products that are then resold or rebranded by another company). 

ZWO and ToupTek are not related. They are entirely different companies. 

[centroid]

1 hour ago, FLO said:

No. They are not.

I don't know where this myth started but it is most definitely not true. 

ZWO cameras are designed and manufactured by ZWO. 

Altair cameras are designed and manufactured by ToupTek in China.

ToupTek is essentially a OEM manufacturer (a company that designs and manufactures products that are then resold or rebranded by another company). 

ZWO and ToupTek are not related. They are entirely different companies. 

There you go, that puts that myth to bed , thanks Steve. However, do they both not use the same Sony 'chip'.

[centroid]

1 hour ago, vlaiv said:

Not sure about that ...

vs

 

You are correct Vlaiv, I should have looked more closely. Put in down to a Senior Moment, or "should have gone to Spec Savers" (a UK phrase) 😅

[ONIKKINEN]

If this ToupTek manufactured camera follows the same logic as my RisingCam (ToupTek manufactured) the conversion factor would be a factor of 100. My model goes from 1-100 in ASCOM and 100-10 000 in the ToupTek driver.

 

The 1-100 ASCOM value corresdponds directly to the relative gain value (not db).

[FLO]

9 minutes ago, centroid said:

... do they both not use the same Sony 'chip'.

My wife's Toyota Verso had a BMW engine but I don't recall it looking or driving like one. 

[johninderby]

And Mercedes used to buy in diesel engines from Ford for their vans a few years ago. Totally irrelevant I know but reminded of it by the above post.

The camera chips may be the same but the way they are implemented and other circuitry is also different and can have a big effect on the way they work.

Edited October 19, 2021 by johninderby

[FLO]

21 minutes ago, johninderby said:

The camera chips may be the same but the way they are implemented and other circuitry is also different.

Yes. When comparing cameras there is so much more to consider. I.e. design, hardware, firmware, drivers, memory buffer, cooler, etc. Also the modular system and accessories built around them.  

It is good we have choice 😇

[centroid]

Yep, and the engine in my new Qashqai is also used by Mercedes, but its basically the same engine. Its all down to saving on development costs. I guess same policy is used by the astro camera manufacturers. 

Anyway back on  the track of the original question, from which the 'thread' digressed.

Here is an extract from a discussion on the Sharpcap forum, which endorses/confirms what I was told elsewhere, and  gives the correlation between the gain figures used by the ASCOM  camera control panel, and those used within Sharpcap, and other software.

"the ASCOM driver shows the gain as a multiple of the lowest gain value, so 1.00x, 2.50x, 6.00x etc.

SharpCap uses numbers that are 100 times bigger, so the equivalents in SharpCap are 100, 250, 600 et"

So, I have a definitive answer to my question.

Edited October 19, 2021 by centroid

[centroid]

1 hour ago, ONIKKINEN said:

If this ToupTek manufactured camera follows the same logic as my RisingCam (ToupTek manufactured) the conversion factor would be a factor of 100. My model goes from 1-100 in ASCOM and 100-10 000 in the ToupTek driver.

 

The 1-100 ASCOM value corresdponds directly to the relative gain value (not db).

This does appear to be the case, thank you. 

Some consistency would be nice 😉

Edited October 19, 2021 by centroid