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"New" Lens Imaging Platform/Request Lens Recommendations

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#1 BenKolt

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Posted 20 August 2019 - 10:06 PM

Greetings!

 

I would very much appreciate recommendations of good quality camera lenses suitable for astrophotography.  I've cobbled together some equipment to mount such lenses with my astronomy cameras, and it is painfully apparent that most of my existing terrestrial lenses are ill-suited!

 

It's not often that I am willing to post such a lousy image (see the next post), but I made a test of this new equipment configuration that I gathered together using mostly pieces and parts I had lying around amongst my astrogear collection.  For terrestrial photography I have an old, venerable Nikon D80 as well as an assortment of Nikon F-mount lenses.  I purchased F-mount adapters for both my QSI 683 and FLI ML16200 cameras and determined that each is properly spaced for these lenses.  I also purchased a PegasusAstro FocusCube 2 and a belt and pulley system that turns the focus ring of the lenses.  Using two spare dovetail plates, I bolted it all together and still had room for a finder scope for autoguiding.  I managed to squeeze a Stellarvue finderscope into a Celestron ring and drilled the Celestron bracket out to bolt to the top plate.  This is definitely a Frankenstein monster of a system with practically every astronomy accessory company represented.  That last statement is an exaggeration, but saying it makes me feel good.

 

Here's a picture of my collection of spare parts flying in formation (taken with that Nikon D80 that I mentioned).  Here I am using my FLI ML16200 (hidden in the back) and FLI CFW2-7.  Attached to it is an old Nikon lens of mine (AF-S VR Zoom-Nikkor 70-300mm f/4.5-5.6G IF-ED) that serves me well for photographing nature, wild animals, even wilder children, but not so much nebulae (more on this later).  You can also see the finderscope with SX Ultrastar M guide camera.  Velcroed to the FW is a small 4-port StarTech industrial USB hub (peaking from behind).  This is all a surprisingly heavy assembly, but it rides well on my Mach1 mount.

 

DSC_1479_Preview01-1.jpg

 

And here's a view from the back camera side:

 

DSC_1480_Preview01-1.jpg

 

What pleases me the most is that I got to reuse lots of spare parts that were otherwise lying around idle.  The FocusCube is bolted onto the cross plate in such a way that it can easily be adjusted for just about any lens / CCD camera combination.  Having used all of this for one night, and one night only, so far, I can say that the focusing appeared to be adequate, although certainly not exercised with a quality lens.  The autoguiding worked just fine at such a wide pixel scale (over 4"/px!).  One very important thing lacking is a mounting ring or two to keep the lens better anchored to the assembly.  There was definitely flexure between the lens and finderscope, and I'm certain the movement was mostly in that lens.  At present I can only anchor the FLI camera to the plate, and having a ring on the lens would have helped immensely with stability.  I know that ADM carries rings of proper size.

 

Next I'll post the lousy image and cuss and discuss it ...

 

Best Regards,

Ben


Edited by BenKolt, 20 August 2019 - 10:36 PM.

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#2 BenKolt

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Posted 20 August 2019 - 10:28 PM

I had a single clear night to test out the gear.  I really wanted to frame NGC 7000 at 300mm FL, so I adjusted the lens all the way out, taped it in place, and started imaging.  I was already aware that these cheaper zoom lenses are typically ill-suited for astrophotography, and now I have one night's test that confirmed this to be true, at least for this particular lens.  I had wanted to image in H-alpha, but after a few tests I determined there was practically no signal there to speak of.  And so I devoted the night to imaging with the L filter.  This is the result of 66 x 300s = 5.5 hr, which under normal circumstances at F5.6 ought to have produced a decent image.  Here I have done a little bit of cropping to account for some image shift (recall the flexure I mentioned above) and noise reduction.

 

NGC7000_L_102-01_1x1_0300s_20190819_-25C.v005A_HT2-1.jpg

 

Here's a zoomed, cropped part of the image showing close-up of some of the brighter stars:

 

NGC7000_L_102-01_1x1_0300s_20190819_-25C.v005B_CROP1-1.jpg

 

The good news is that my stars are nicely circular.  The bad news is that there are massive amounts of reflections and other issues resulting in lots of pretty concentric rings around those stars!

 

I was already aware that lenses of these types simply have far too many elements in them to make them suitable for this kind of imaging.  But, I grabbed what I had in hand, and I had a fun night testing out my Frankenstein's monster of a lens imaging system.  Autofocusing worked as well as it could, autoguiding worked well, and in the end I got a North American nebula image that looks fair when I take my glasses off.  Enjoy this image, because I won't be using this lens ever again for astrophotography!

 

Thanks for indulging me with these posts, and let me end with my opening question:

 

What prime lenses (F-mount preferred as I have the necessary gear) would you recommend for various FL's?  I'd like to start with something on the order of 300mm and work my way down to 200mm, then smaller, eventually perhaps even down to 35mm for really wide sky shots.

 

Best Regards,

Ben

 

P.S.  I forgot to mention that I do have an AF-S Nikkor 35mm 1:1.8G, but I have not tested it yet.  Should I expect this to give me some decent ultra-wide images or not?


Edited by BenKolt, 20 August 2019 - 10:38 PM.


#3 gunny01

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Posted 21 August 2019 - 06:59 AM

  You might want to ask the lens question on the dslr forum Ben.  I know that the sigma f1.4 40mm was recently reviewed and seems to be  a winner.  You'll have to approach wide angle lens' carefully with respect to ca, astigmatism, coma.  Sigma has some losers in the arena.

 

  I had a rig similar to yours for the stt 8300 and the ring adapter was awful.  Very poor machining. I believe pparts makes the adapter rings, so you may want to look there. At least your rig did better than mine.  Good luck.


Edited by gunny01, 21 August 2019 - 07:00 AM.


#4 2ghouls

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Posted 21 August 2019 - 07:43 AM

The new-ish Sigma Art 105mm f/1.4 looks like a winner. Check out Jerry Lodriguss’s samples on the DSLR forum. I hope to rent one later this month to try it out.

If you want to go cheaper than the Sigma Art line, Rokinon manual focus primes are often pretty good for the price. The 135mm f/2.0 is well-regraded and widely used in AP.

#5 fetoma

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Posted 21 August 2019 - 08:31 AM

http://www.astropix....rop/lenses.html



#6 BenKolt

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Posted 21 August 2019 - 08:53 AM

  You might want to ask the lens question on the dslr forum Ben.  I know that the sigma f1.4 40mm was recently reviewed and seems to be  a winner.  You'll have to approach wide angle lens' carefully with respect to ca, astigmatism, coma.  Sigma has some losers in the arena.

 

  I had a rig similar to yours for the stt 8300 and the ring adapter was awful.  Very poor machining. I believe pparts makes the adapter rings, so you may want to look there. At least your rig did better than mine.  Good luck.

Thanks, gunny!  I had completely forgotten about that forum as I don't usually frequent it.

 

I assume that you are referring to the mount ring to attach the lens to the FW, right?  Otherwise, I don't quite follow which part you are talking about.

 

The new-ish Sigma Art 105mm f/1.4 looks like a winner. Check out Jerry Lodriguss’s samples on the DSLR forum. I hope to rent one later this month to try it out.

If you want to go cheaper than the Sigma Art line, Rokinon manual focus primes are often pretty good for the price. The 135mm f/2.0 is well-regraded and widely used in AP.

Thanks, Nico, will do.

 

Thanks for the link, Frank.  I skimmed through the article this morning and will read through more carefully later.

 

The recommendation here is to stay away from Nikon DX lenses with full-sized sensors as there can be vignetting.  I think I got by OK on that count.

 

Ben


Edited by BenKolt, 21 August 2019 - 08:56 AM.


#7 gunny01

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Posted 21 August 2019 - 09:47 AM

https://www.cloudyni...300m-stf-8300m/.  These are available for other cameras/fw also.  The item here is what I used and sent back.  The bayonet is very poorly made.



#8 BenKolt

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Posted 21 August 2019 - 10:40 AM

https://www.cloudyni...300m-stf-8300m/.  These are available for other cameras/fw also.  The item here is what I used and sent back.  The bayonet is very poorly made.

I see.  Sorry to hear about that!  The adapter for the FLI FW is small and little hard to get on and off, but the lenses seem to fit on well.  I haven't really used the QSI adapter yet, just test it out.  It's a more substantial piece and has a mechanism to lock in the lens aperture opening if needed.  This weekend I'll mess around with it some more.



#9 lucam

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Posted 21 August 2019 - 04:40 PM

Ben, I built a similar set up for imaging with camera lenses last year and had quite a bit of fun with it. This Summer, I have been focusing more on high-resolution imaging and have not spent any time with ultra-wide field imaging. I used a Rokinon 135 f2 primarily and it is an excellent lens. I used in with a ZWO ASI183MM Pro with tiny pixels (2.4um) and it did quite well. There was some tilt that I never fully got rid of, but these were really my first imaging projects, so I wasn't too picky. 

 

This is a picture of the setup:

 

get.jpg?insecure

 

Similar to you, I used a wide Vixen bar with space for the camera and lens, as well as guidescope. In the center, I velcroed a dew heater. I did use an ADM ring to hold the camera lens and that helps with keeping everything steady and aligned. I used a Rigel focusing motor and controller. It has the disadvantage that each lens needs a big gear on the focus ring, but it works well and doesn't slip. Backlash is not an issue. 

 

Cygnus loop with Rokinon 135mm and ZWO ASI183MM Pro, Astrodon 3nm Ha and OIII:

 

get.jpg?insecure

 

I also used a Rokinon 35mm f1.4 lens for a two panel mosaic of most of Cygnus. I have never finished processing that data. The stars are pretty bad in the corners and have had better data to play with. In general, I think that these very wide lenses are challenging to use for astro work. Possible exceptions are the Signa 50mm ART or lenses of similar quality. 

 

I have recently bought a Canon 200mm f2.8 and have high hopes for this lens with the ZWO ASI1600MM Pro, similar filed of view of my previous setup but with bigger aperture. One thing that you may want to consider is purchase some step-down filter rings. The lens gains sharpness and you don't end up with diffraction artifacts around bright stars due to the polygonal iris. I have done a little bit of testing with a 52mm internal diameter filter with the Canon 200mm lens and it improves star shapes while keeping effective aperture at a respectable f4. 


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#10 Starblind

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Posted 21 August 2019 - 06:21 PM

Interesting setup, and interesting question.  I'm using lenses most of the time.  Unfortunately most prime lenses are not cheap.  I do a lot of astrophotography with lenses because I do a lot of regular photography, it actually pays for itself some of the time.  I did quite a lot of testing to both build my rig and determine what I could get out of it.  Interestingly, the two main lenses I use at the moment are a Tamron 70-200 G2 and a Kenko 200mm F4 (4 element Petzval design).  Both work really well with an ASI1833MM Pro, and I built a special rig to mount that and the focuser (picture below) using SmallRig photography accessories to custom configure everything so it's fully adjustable, and I can swap lenses easily.  The main problem is lens support, anything without a lens collar/foot is hard to use.  My next purchase will be a Nikon 300mm F4 (about $750) to complete the set of 135 to 300mm.  I still use my 72mm refractor occasionally but for wide field it's all lenses.  An older 70-200 Nikon or Canon with a lens collar/foot and a manual F stop adjustment is perfect, they work better at F4, but even the newer ones wide open are pretty good.  There is an image in my gallery shot with the Kenko F4, which comes with a tripod foot/ring, but they are hard to get hold of lately, I got mine for $200, but that price has doubled since two years have passed as they are no longer made.  I might be interested in selling it now I have my 70-200 mounted and working.

 

Bob

 

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#11 Coconuts

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Posted 21 August 2019 - 06:58 PM

If you want to check the field corner performance of a lens before buying, which given how many of them have real issues there is a good idea, you should check the reviews at http://www.lenstip.com.  They use an artificial star to reveal corner aberrations.  If you have the budget, a few Sigma Art lenses (40 mm f/1.4. 85 mm f/1.4, 105 mm f/1.4, and 135 mm f/1.8) are awesome; a number of the other Art lenses, not so much. 

 

For comparison, here is the Sigma Art 40 mm field corner performance:

https://www.lenstip...._and_bokeh.html

 

And here is their far worse 24 mm f/1.4:

https://www.lenstip...._and_bokeh.html

 

But in the four lenses cited above, Sigma Art is well ahead of the other players, including Canon and Nikon.

 

All the best,

 

Kevin


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#12 BenKolt

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Posted 22 August 2019 - 12:03 AM

Ben, I built a similar set up for imaging with camera lenses last year and had quite a bit of fun with it. This Summer, I have been focusing more on high-resolution imaging and have not spent any time with ultra-wide field imaging. I used a Rokinon 135 f2 primarily and it is an excellent lens. I used in with a ZWO ASI183MM Pro with tiny pixels (2.4um) and it did quite well. There was some tilt that I never fully got rid of, but these were really my first imaging projects, so I wasn't too picky. 

 

This is a picture of the setup:

 

get.jpg?insecure

 

Similar to you, I used a wide Vixen bar with space for the camera and lens, as well as guidescope. In the center, I velcroed a dew heater. I did use an ADM ring to hold the camera lens and that helps with keeping everything steady and aligned. I used a Rigel focusing motor and controller. It has the disadvantage that each lens needs a big gear on the focus ring, but it works well and doesn't slip. Backlash is not an issue. 

 

Cygnus loop with Rokinon 135mm and ZWO ASI183MM Pro, Astrodon 3nm Ha and OIII:

 

get.jpg?insecure

 

I also used a Rokinon 35mm f1.4 lens for a two panel mosaic of most of Cygnus. I have never finished processing that data. The stars are pretty bad in the corners and have had better data to play with. In general, I think that these very wide lenses are challenging to use for astro work. Possible exceptions are the Signa 50mm ART or lenses of similar quality. 

 

I have recently bought a Canon 200mm f2.8 and have high hopes for this lens with the ZWO ASI1600MM Pro, similar filed of view of my previous setup but with bigger aperture. One thing that you may want to consider is purchase some step-down filter rings. The lens gains sharpness and you don't end up with diffraction artifacts around bright stars due to the polygonal iris. I have done a little bit of testing with a 52mm internal diameter filter with the Canon 200mm lens and it improves star shapes while keeping effective aperture at a respectable f4. 

Thanks, Luca!  That's a great looking rig, and I appreciate the information.  And thank you for the lens recommendations.  Sigma Art keeps coming up as a premium chioce, and I've learned now that they are quite the investment!

 

Interesting setup, and interesting question.  I'm using lenses most of the time.  Unfortunately most prime lenses are not cheap.  I do a lot of astrophotography with lenses because I do a lot of regular photography, it actually pays for itself some of the time.  I did quite a lot of testing to both build my rig and determine what I could get out of it.  Interestingly, the two main lenses I use at the moment are a Tamron 70-200 G2 and a Kenko 200mm F4 (4 element Petzval design).  Both work really well with an ASI1833MM Pro, and I built a special rig to mount that and the focuser (picture below) using SmallRig photography accessories to custom configure everything so it's fully adjustable, and I can swap lenses easily.  The main problem is lens support, anything without a lens collar/foot is hard to use.  My next purchase will be a Nikon 300mm F4 (about $750) to complete the set of 135 to 300mm.  I still use my 72mm refractor occasionally but for wide field it's all lenses.  An older 70-200 Nikon or Canon with a lens collar/foot and a manual F stop adjustment is perfect, they work better at F4, but even the newer ones wide open are pretty good.  There is an image in my gallery shot with the Kenko F4, which comes with a tripod foot/ring, but they are hard to get hold of lately, I got mine for $200, but that price has doubled since two years have passed as they are no longer made.  I might be interested in selling it now I have my 70-200 mounted and working.

 

Bob

 

And thank you, Bob for showing me your equipment.  I will also be employing dew heaters next time, but I wasn't able to get that together in time before.  I'll take a look at your gallery.

 

If you want to check the field corner performance of a lens before buying, which given how many of them have real issues there is a good idea, you should check the reviews at http://www.lenstip.com.  They use an artificial star to reveal corner aberrations.  If you have the budget, a few Sigma Art lenses (40 mm f/1.4. 85 mm f/1.4, 105 mm f/1.4, and 135 mm f/1.8) are awesome; a number of the other Art lenses, not so much. 

 

For comparison, here is the Sigma Art 40 mm field corner performance:

https://www.lenstip...._and_bokeh.html

 

And here is their far worse 24 mm f/1.4:

https://www.lenstip...._and_bokeh.html

 

But in the four lenses cited above, Sigma Art is well ahead of the other players, including Canon and Nikon.

 

All the best,

 

Kevin

And thanks again for this information, Kevin!  I'll be pondering my next purchase a while longer, and the lenstip site will come in handy.

 

Best Regards,

Ben



#13 Bart Declercq

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Posted 22 August 2019 - 02:30 AM

Since a few days, I've been using the combination ASI1600MM-Cool + Canon 300mm F/4L USM (the ancient, non-IS variant) + https://astromechanics.org/ Canon adapter (that provides ascom control of the aperture and focus-motor for Canon lenses).

I'm still working on completely correcting for sensor-tilt, but the first results are so encouraging that I'm going to buy a second Canon 300mm F/4L USM to go with a second camera on the same mount to double my imaging speed.

 

First result (H-alpha in part due to the moon still being quite close to full) - 220min NGC7000 - https://flic.kr/p/2h2meqM

 

The current setup can be seen at https://photos.app.g...BPidSw94BJbtdk8

 

Using Sequence Generator Pro's autofocus functionality, I get a perfect focus curve and also very good reproducibility (multiple consecutive autofocus attempts all end up on the same step-value, perhaps one step up or down occasionally)


Edited by Bart Declercq, 22 August 2019 - 02:31 AM.


#14 gunny01

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Posted 22 August 2019 - 08:01 AM

Ben, I built a similar set up for imaging with camera lenses last year and had quite a bit of fun with it. This Summer, I have been focusing more on high-resolution imaging and have not spent any time with ultra-wide field imaging. I used a Rokinon 135 f2 primarily and it is an excellent lens. I used in with a ZWO ASI183MM Pro with tiny pixels (2.4um) and it did quite well. There was some tilt that I never fully got rid of, but these were really my first imaging projects, so I wasn't too picky. 

 

This is a picture of the setup:

 

get.jpg?insecure

 

Similar to you, I used a wide Vixen bar with space for the camera and lens, as well as guidescope. In the center, I velcroed a dew heater. I did use an ADM ring to hold the camera lens and that helps with keeping everything steady and aligned. I used a Rigel focusing motor and controller. It has the disadvantage that each lens needs a big gear on the focus ring, but it works well and doesn't slip. Backlash is not an issue. 

 

Cygnus loop with Rokinon 135mm and ZWO ASI183MM Pro, Astrodon 3nm Ha and OIII:

 

get.jpg?insecure

 

I also used a Rokinon 35mm f1.4 lens for a two panel mosaic of most of Cygnus. I have never finished processing that data. The stars are pretty bad in the corners and have had better data to play with. In general, I think that these very wide lenses are challenging to use for astro work. Possible exceptions are the Signa 50mm ART or lenses of similar quality. 

 

I have recently bought a Canon 200mm f2.8 and have high hopes for this lens with the ZWO ASI1600MM Pro, similar filed of view of my previous setup but with bigger aperture. One thing that you may want to consider is purchase some step-down filter rings. The lens gains sharpness and you don't end up with diffraction artifacts around bright stars due to the polygonal iris. I have done a little bit of testing with a 52mm internal diameter filter with the Canon 200mm lens and it improves star shapes while keeping effective aperture at a respectable f4. 

  Hi Luca,

 

    I recently got a Nitecrawler for my fsq and really like it.  Ron makes a tip tilt adjuster called the sidewinder that may help with  tilt problems.  He also makes various adapter at reasonable prices.  My two 1600's had serious problems with tilt, but with this sidewinder, I may reconsider and get another 1600 and try again. HTH.

 

Since a few days, I've been using the combination ASI1600MM-Cool + Canon 300mm F/4L USM (the ancient, non-IS variant) + https://astromechanics.org/ Canon adapter (that provides ascom control of the aperture and focus-motor for Canon lenses).

I'm still working on completely correcting for sensor-tilt, but the first results are so encouraging that I'm going to buy a second Canon 300mm F/4L USM to go with a second camera on the same mount to double my imaging speed.

 

First result (H-alpha in part due to the moon still being quite close to full) - 220min NGC7000 - https://flic.kr/p/2h2meqM

 

The current setup can be seen at https://photos.app.g...BPidSw94BJbtdk8

 

Using Sequence Generator Pro's autofocus functionality, I get a perfect focus curve and also very good reproducibility (multiple consecutive autofocus attempts all end up on the same step-value, perhaps one step up or down occasionally)

  See above Bart.  HTH


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#15 BenKolt

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Posted 22 August 2019 - 09:37 AM

Since a few days, I've been using the combination ASI1600MM-Cool + Canon 300mm F/4L USM (the ancient, non-IS variant) + https://astromechanics.org/ Canon adapter (that provides ascom control of the aperture and focus-motor for Canon lenses).

I'm still working on completely correcting for sensor-tilt, but the first results are so encouraging that I'm going to buy a second Canon 300mm F/4L USM to go with a second camera on the same mount to double my imaging speed.

 

First result (H-alpha in part due to the moon still being quite close to full) - 220min NGC7000 - https://flic.kr/p/2h2meqM

 

The current setup can be seen at https://photos.app.g...BPidSw94BJbtdk8

 

Using Sequence Generator Pro's autofocus functionality, I get a perfect focus curve and also very good reproducibility (multiple consecutive autofocus attempts all end up on the same step-value, perhaps one step up or down occasionally)

Thanks for the inputs, Bart!  In the future I may indeed get Canon adapters for my CCD's in order to expand the collection.




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