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Canon 135 F2L test

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#1 astrohound24

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Posted 21 September 2020 - 08:48 PM

I am testing my new lens tonight. I am grabbing series of images between F2 and F2.8. The reason I did it is because I noticed wide open at F2 not as sharp. After looking more tonight I am pretty pleased with it from F2.5 and onward. I used BYEOS and made sure focus was spot on through the F stop range. I am inexperienced on judging lenses, but I think it’s a keeper. As always I value opinions here and people that know more than me. Welcome all assessments in helping me determine if I should hang on to it. Thanks everyone. Posted images below of single frames at each F stop.

Greg


Edited by astrohound24, 22 September 2020 - 02:16 AM.


#2 astrohound24

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Posted 21 September 2020 - 09:52 PM

Here is a frame at F2.0

 

 

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Edited by astrohound24, 21 September 2020 - 09:53 PM.


#3 astrohound24

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Posted 21 September 2020 - 09:54 PM

Here is F2.2

 

 

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#4 astrohound24

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Posted 21 September 2020 - 09:59 PM

And F2.8 for 60 second exposure.

 

 

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#5 ngc7319_20

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Posted 21 September 2020 - 10:15 PM

Some years ago I tested this lens with similar results.  It is better stopped down a bit.  My impression is that you have a good sample -- the corners are all fairly clean with similar focus and not much coma.  It may be easier to tell the performance on full resolution images -- maybe you can post a link somehow.


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#6 astrohound24

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Posted 21 September 2020 - 10:26 PM

I can post some and will. I think it looks fine at F2.8. I guess I was hopeful it would be a little better wide open but at F2.8 still a lot of light gathering. Thanks for looking and I will get some links to full resolution.

 

Greg 



#7 petert913

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Posted 21 September 2020 - 10:28 PM

Stacking a few of these frames will really make things pop !


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#8 astrohound24

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Posted 21 September 2020 - 10:39 PM

https://drive.google...ew?usp=drivesdk
 

full resolution F2



#9 astrohound24

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Posted 21 September 2020 - 10:41 PM

https://drive.google...ew?usp=drivesdk
 

full resolution at F2.2



#10 astrohound24

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Posted 21 September 2020 - 10:42 PM

Full resolution F2.5

 

https://drive.google...ew?usp=drivesdk



#11 astrohound24

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Posted 21 September 2020 - 10:43 PM

And finally full resolution F2.8 where I think it looks best.

 

https://drive.google...ew?usp=drivesdk



#12 astrohound24

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Posted 21 September 2020 - 10:45 PM

I hope those links help. They are just JPEGs but maybe better. 



#13 astrohound24

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Posted 21 September 2020 - 11:25 PM

I was really proud of my Skytracker Pro tonight. I polar aligned good and I think at 200 seconds she looked like she tracked well. This was F2.8. A little washed out though.

 

Greg  

 

https://drive.google...ew?usp=drivesdk
 


Edited by astrohound24, 21 September 2020 - 11:26 PM.


#14 awong101

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Posted 21 September 2020 - 11:45 PM

I was really proud of my Skytracker Pro tonight. I polar aligned good and I think at 200 seconds she looked like she tracked well. This was F2.8. A little washed out though.

 

Greg  

 

https://drive.google...ew?usp=drivesdk
 

1) What's that line running across your image from Northwest to Southeast?

 

2) I see slight star trails when I zoom in

 

Otherwise, that looks great! Is that with or without a filter?



#15 astrohound24

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Posted 21 September 2020 - 11:51 PM

Satellite crossed the field a couple times. It was there and then gone. No filter. I kept it out since I was testing the lens. It was dark sky site at my friends mothers house. It’s just lovely up on that property. Thanks!

 

Greg



#16 awong101

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Posted 22 September 2020 - 12:04 AM

Satellite crossed the field a couple times. It was there and then gone. No filter. I kept it out since I was testing the lens. It was dark sky site at my friends mothers house. It’s just lovely up on that property. Thanks!

 

Greg

I asked about the filter because there's a lot of red? Maybe the experts can chime in, but I think you can use a filter here?



#17 astrohound24

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Posted 22 September 2020 - 01:12 AM

It’s a modified camera but yeah the light pollution dome from neighboring Paducah wasn’t far. It’s dark but I shouldn’t say dark sky site because that would be in Land Between the Lakes which is near where I live. I have used a CLS-CCD here before and it is nice. I just left it out tonight testing my lens. Thanks!

 

Greg



#18 ngc7319_20

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Posted 22 September 2020 - 06:46 AM

These are the enlarged corners and center of your full-resolution F/2.8 image.  Overall I would say this is an excellent lens.  The corners are slightly softer than the center, but its pretty close and much better than most lenses I've seen.  The top left shows a small amount of elongation, but is very acceptible.  I would be very happy with this lens.

 

LIGHT_60s_1600iso_f2-8_corners_3x.jpg


Edited by ngc7319_20, 22 September 2020 - 06:48 AM.

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#19 astrohound24

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Posted 22 September 2020 - 07:24 AM

These are the enlarged corners and center of your full-resolution F/2.8 image. Overall I would say this is an excellent lens. The corners are slightly softer than the center, but its pretty close and much better than most lenses I've seen. The top left shows a small amount of elongation, but is very acceptible. I would be very happy with this lens.

LIGHT_60s_1600iso_f2-8_corners_3x.jpg


Thanks for the work you did for comparing those. Yes I will be hanging on to this one. I am looking forward to getting out and shooting with it. Thanks so much again.

#20 DubbelDerp

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Posted 22 September 2020 - 08:48 AM

I'd shoot that lens wide open without a second thought. As long as you can get sharp focus at f/2, and it looks like you can, that lens has some great potential.

 

The red cast is completely normal for a H-a modded camera when shooting daylight white balance. If you want them to display in more "correct" color, you can shoot a custom white balance with a white or neutral grey card in sunlight, and then the background sky will be a more accurate color on the back of camera LCD or in your typical display programs. But most astro-specific programs ignore the camera white balance anyways, so.. meh. I wouldn't worry about it. You'll probably color balance in post processing either way. 


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#21 astrohound24

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Posted 22 September 2020 - 09:17 AM

I'd shoot that lens wide open without a second thought. As long as you can get sharp focus at f/2, and it looks like you can, that lens has some great potential.

The red cast is completely normal for a H-a modded camera when shooting daylight white balance. If you want them to display in more "correct" color, you can shoot a custom white balance with a white or neutral grey card in sunlight, and then the background sky will be a more accurate color on the back of camera LCD or in your typical display programs. But most astro-specific programs ignore the camera white balance anyways, so.. meh. I wouldn't worry about it. You'll probably color balance in post processing either way.


Yep I will do that. It is focusing fine wide open and might as well take advantage of all that light gathering power. Now to learn to take flats and learn to process. A process that will of course take time. Having a lot of fun with this. I don’t think I have ever enjoyed anything so much. It’s been so addictive. My wife thinks I have lost my mind lol. Thanks for all your help! All of you have been great and full of knowledge.

Greg

#22 astrohound24

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Posted 22 September 2020 - 12:18 PM

I thought I would post picture of the lens. It sure is a big ole piece of glass. 

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#23 astrohound24

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Posted 22 September 2020 - 12:19 PM

One without the hood.

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