Anyone using an EOS 60Da?

Discussion in 'Image Capture' started by Maneesh Yadav, Sep 7, 2018.

  1. Maneesh Yadav

    Maneesh Yadav Cyanogen Customer

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    I'm in the process of setting up my Canon EOS 60Da for imaging with hyperstar on a C14 Edge HD (feathertouch/microtouch focuser). I'm running into some basic problems initial focusing on a focus star. The star seems really big according to MaximDL autofocus (or FocusMax) and I don't trust I understand what is going on.

    I'm decided to test EOS 60Da on my AP 6-inch (FLI DF2 focuser) where things were working great with the SBIG 402 ME. The purpose was to control for any possible problem in the optical train of the C14, since I haven't used that scope for imaging yet and the feather/micro touch was just installed. The stars on the EOS 60Da seem to be big according the the HFD measurements I see in MaximDL and FocusMax (HFD is always >12).

    I can't remember what star I was on in the attached screenshot but I did try a a variety of magnitudes between 1 and 6 without any apparent change in the HFD.

    If there is an issue, it seems to be in the camera. Is this normal for DSLRs or this camera? Is there a stale setting that could be affecting the imaging or the calculation? Can anyone else confirm that they are using an EOS 60Da in this way and don't see this sort of behavior?

    May be doing something very foolish here, but I can't figure it out.
     

    Attached Files:

  2. Colin Haig

    Colin Haig Cyanogen Customer

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    Your focus star is too bright I think. Keep in mind the pixels on the 60Da are 4.3um in a 5184 x 3456 bayer array (RGGB), so you might want to bin 2x2 to get started.
    By comparison, the ST402 has 9um pixels 765x510 all mono.
    So the 60Da pixels are 1/4 the size. Binning them 2x2 might give you more like the result you are expecting.

    Looking at the V-curve, am betting it will pop into focus somewhere in the 900's of position am guessing.
    So refine that V-curve (eg start the focus range around 750 to 1100, and finer steps. Then use a smaller step size.) It will take a while.
    The hyperstar is going to be challenging as the scope is so fast in that arrangement (f/2 ish?)
     
  3. Maneesh Yadav

    Maneesh Yadav Cyanogen Customer

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    Thanks for the advice Colin. I didn't record the images systematically as I should have (I tried FocusMax too and with 2x2 binning), but using a dimmer (5.something) star didn't seem to help.

    I'll try again and see if I missed something.Yes I am pretty certain that the camera is in focus somewhere around the minimum in the V-curve, so that makes sense. The stars seem worse on the back of the C14.

    I notice with he 60Da the background noise seems to be higher, don't see the same contrast between the star and background for reasonably long exposures.

    Ah:
    https://diffractionlimited.com/help/maximdl/DSLR_Focusing_Tutorial.htm

    Maybe this was the issue:

    "DSLR cameras always have several Readout Mode options. Although it is the best option during imaging, do not use the Raw Monochrome option for focusing, because the color Bayer matrix will make it impossible make proper measurements on the star. You can use the Raw Color mode; however, for most cameras the image download time is slow enough to be very inconvenient for focusing. The best option is usually to use the JPEG Monochrome mode. The image downloaded is noisier, lower bit depth, and has compression artifacts; however, the image degradation is not bad enough to significantly affect focus measurements."
     
  4. Colin Haig

    Colin Haig Cyanogen Customer

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    Background noise will be much higher on the 60Da - the chip isn't cooled, and that model is noisier (I own own).
     
  5. Maneesh Yadav

    Maneesh Yadav Cyanogen Customer

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    Yes indeed. Mentioned it to see if visible bg was apparent in other people's systems when focusing on stars (in case that had something to do with the weird HFDs). I have a good feeling changing the camera readout mode will fix things since I know the whole system otherwise is working fine.
     
  6. Maneesh Yadav

    Maneesh Yadav Cyanogen Customer

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    I'm still having problems getting a food focus curve in MaximDL and FocusMax even after testing with "JPG Monochrome" mode.
    I've seen that the min HFD can change a lot (12 previously, in my last run not much below 40), I think the key factor is the exposure time; next run I'll try and make sure that I select the right magnitude for an appropriate flux for a 0.1s exposure. My guess is that the higher background on the DSLR inflates the HFDs so I need to get the right magnitude in as short exposure as I can. Am I the only one having trouble focusing with the EOS 60D?

    Colin, do you use autofocus with your EOS 60Da? What sort of HFDs do you see?
     
  7. Colin Haig

    Colin Haig Cyanogen Customer

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    Maneesh, I havent used that camera in months, so can't give you any useful info.
     
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  8. SkyHawk

    SkyHawk Cyanogen Customer

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    Hi Maneesh,
    I use Canon 60Da on occasion with LX200 ACF 12 inch and AT65EDQ scopes. I use focusMax for focusing with a Optic TCF-S focuser. I don't recall what the minimum HFD is but I use around a mag 7 star to focus on with the LX200.

    Canon Setup:
    High ISO noise reduction=Disabled
    Long exposure noise reduction=Off
    Auto Power off=Disabled
    Sensor Cleaning>Auto Clean=Disabled
    ISO=800
    Quality=Raw

    Maxim setup:
    Camera Model=Canon Eos II
    Mirror Settle Time=1 second
    Binning=1
    Readout Mode=RAW Monochrome

    When running V-curves I use a step size of what ever the Critical Focus Zone calculations are for the scope. For the LX200 I use 100 steps for the optic focuser.

    Keep the Center value in the the VCurve Sequence at the focus point. This will shift during the Vcurve measurements and cause the absolute value of the left and right slopes to increase. Depending on which side of focus the center position is on will cause either the right slope or left slope to be higher value.

    It's important to have to near focus position in the linear portion of the slope. Too low of a near focus value can throw the focus off.

    Bill
     
  9. Maneesh Yadav

    Maneesh Yadav Cyanogen Customer

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    Thanks for the detailed information Bill. It is interesting that you are focusing with "RAW Monochrome". I noticed that "JPG Monochrome" would occasionally seem to get stuck (I seemed to keep reading an old frame).

    I'm going to move forward and put the hyperstar on the C14 with the EOS 60d, even though don't seem to have yet validated it is working on the back of my AP-6inch. It sure seems to be a camera setting somewhere or the choice of star, lets see if I can find it.

    If you do happen to find your HFDs/fluxes/exposure times (for focusing) anywhere, please do post as it may help me find my problem.
     
  10. SkyHawk

    SkyHawk Cyanogen Customer

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    Hi Maneesh,
    It maybe some time before I use the 60Da. I found a focusmax run I did in July which I am attaching. This is with a LX200ACF 12inch and an optic 6.2 focal reducer.

    Hope it helps,
    Bill
     

    Attached Files:

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