Buying an Astromodded Sony: A7 vs A7s vs A6000 - Forums

Topic starter

Jan 5, 2022

I want to pick up an astromodded Sony alpha camera. I have a variety of lenses already for these cameras. I am debating between the following:

Camera / Sensor size / MP / Pixel Pitch / Strength

- a6000 / APS-C / 24 MP / 3.88 um / More reach, less $$
- A7 / Full frame / 24 MP / 5.93 um / Larger pixel size, higher MP for cropping
- A7S / Full frame / 12 MP / 8.32 um / Large pixel size grabs light, 12 MP doesn't provide as much space for cropping

I used the Astrobin search function and it seems the A7S is the more popular astrocamera and produces beautiful images but also those images were supported with high quality OTA or lenses.

Curious what your thoughts are?

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Gernot Schreider

Jan 5, 2022

First thought is that I would consider the field of view, so you need to consider which objects you want to image and which lenses you have. Then calculate the FOV and check with Stellarium how your images would capture your favorite objects. I guess this is the approach for considering "cropping" what you already mentioned.
It makes a lot of difference if you can image an object across your FOV or if you only fill 10% of the image.

Second thought that comes to my mind is the optimum ISO value to use and what dynamic scale this provides. The more the better, since this will provide contrast to your pictures and determine the exposure times.

There is no clear answer to such a question. You can only optimize towards a preferred usage scenario.

Third thought is money. I do not know what gear you have besides the lenses. Consider if you want to invest in a expensive full frame camera vs cheap APS-C and have less money to spend on a quality mount or other needed gear.

Fourth thought is if you start with this hobby, start with the gear you have and master the handling before investing big in next gear. There is always the next best gear you want if you are in this hobby, but this should not stop you to live the hobby with what you have at hand.

CS
Gernot

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Jonathan Piques

Jan 5, 2022

I second what the above poster said. If one of the main drivers for considering an astro-modded Sony camera is the fact you’re already invested in lenses, really think about what it is you want to image. Even long focal length lenses by photography standards are pretty wide by astrophotography standards. For context, my first refractor had a focal length of 350mm and it was considered very wide field. Cropping in may help a little, but it’s no substitute at all for having the right focal length to begin with—you won’t be happy with the results. If you’re all about super wide field images, then go for it. Otherwise, maybe consider how else you could spend that money, possibly on a decent refractor / mount. I know that’s probably not what you wanted to hear but the reason I responded was I didn’t want you to spend money on something that ultimately potentially disappointed you. This hobby is difficult enough without that. Hope that helps some…good luck!

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andrea tasselli

Frequent contributor

Jan 5, 2022

Frankly, for the price of a used (and old tech) Sony A7/A7S plus the price of astro-modding it I'd go for a cooled CMOS dedicated camera instead. Note also the issue with the Sony firmware and the issue with its "star-eating" habit.

Astro-chicken

Topic starter

Jan 5, 2022

I've already considered much of the above including target, budget, etc… I have about a dozen lenses ranging from 50mm for wide field shots (e.g. Barnard's Loop) up to a 600mm f6.3 lens that competes with a lot of the larger refractors (also a costs as much!). With focal lengths of 50mm to 600mm and even more with teleconverters there are hundreds of targets available to me. At this point I don't feel the need to invest in an additional piece of glass.

I've considered a cooled CMOS. However, I have a lot of cloud cover where I live so a mono cooled camera won't work for me because of limited time. The color cooled CMOS with decent size sensors are $2500-4000 as far I can tell but I can pick up a used A7S and get it astromodded all for under $1400. That's a big difference. As for the star eater problem I am already shooting with an unmodded Sony and I'm just not seeing it. I'm the effect is real but unless you are pixel peeping its a non-issue for a hobbyist like me.

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Steven

Jan 5, 2022 · Edited: Jan 5, 2022

Sony camera's are alright. But any reason why you're going there, other than the lenses? And more importantly, what are your plans after?
It's not that any of the camera's you mention can't work.. more wether or not it's worth investing in one.

Astrophotography is a great hobby, but it's a hobby that has a bit of a rabbit hole to go in when it comes to gear and the cost of it.
Depending on how serious you plan on taking the hobby and where you want to take the hobby, it might not be worth investing into gear that will, in the end, get replaced. And future-proofing your gear can be a handy thing.

Sony lenses are fine, but most are not made with astrophotography in mind. It's not impossible to get nice result, but there are more than enough "lens vs telescope" videos on YouTube where telescopes get far better results.. for good reason. - So there is a good chance that in some time you might want to upgrade to an actual scope, because you aren't getting the focal length you want from the lenses, or the aperture, or the star shapes, or whatever other reason.. and then you're "stuck" with the Sony camera..

So, if the main 'drive' for the camera choice, are the lenses.. you might run into that issue.

If you plan on sticking to the Sony mirrorless it could obviously work.
If that is the case;

Like Gernot suggested. Use "Stellarium" and look at the field of views that you're working with and hoping to achieve.
with the varying pixel sizes and sensor sizes, it might be worth looking at that to make sure things work for you.

the A7S is probably going to give you the best low-light performance, it's the whole point of that camera. But wether or not it works for you, is a different matter.
Since you're dealing with very large pixels. So you might be undersampling your images with most lenses under 400-500mm.

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Jonathan Piques

Jan 5, 2022

Oh man a 600mm lens? That’s intense. I’m jealous. Have always wanted a wildlife lens like that. Then I say go for it, see how it goes. Only other relatively minor thing to think about is focusing: not sure how that’s going for you currently, and if you image unattended etc… then autofocusing through the night may be a consideration. On the camera itself, personally I’d lean towards the A7S just to keep the noise down, but again that all depends on how much integration time you plan on getting balanced with how much you think you’ll need to crop. If you grab more data that cuts down on the advantage of the larger pixels, but won’t negate it. Sounds like you’ve got fairly decent options in terms of focal length so the need to crop may be minimal. Good luck man!

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Jonathan Piques

Jan 5, 2022

Oh and PS, does your name come from the Space Quest computer games from the early 90s??

Astro-chicken

Topic starter

Jan 5, 2022

Jonathan Piques:
Oh and PS, does your name come from the Space Quest computer games from the early 90s??

No the name comes from my obsession with chickens. I collect rare breeds and raise them. Spending evenings in the backyard watching them is very relaxing and entertaining.

Jonathan Piques:
Oh man a 600mm lens? That’s intense. I’m jealous. Have always wanted a wildlife lens like that. Then I say go for it, see how it goes. Only other relatively minor thing to think about is focusing: not sure how that’s going for you currently, and if you image unattended etc… then autofocusing through the night may be a consideration. On the camera itself, personally I’d lean towards the A7S just to keep the noise down, but again that all depends on how much integration time you plan on getting balanced with how much you think you’ll need to crop. If you grab more data that cuts down on the advantage of the larger pixels, but won’t negate it. Sounds like you’ve got fairly decent options in terms of focal length so the need to crop may be minimal. Good luck man!

That's exactly what I got the 600mm lens. It's amazing for wildlife. Cost as much as my first car though!

Thanks for your thoughts. I was leaning towards the A7S as well. It has an insanely high ISO (not useful for astrophotography) but you can actually see nebula on the LCD screen if you crank it up. I thought that doing some visual astronomy with friends using the camera might be cool thing to do with visiting friends and family.

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Andy Wray

Jan 5, 2022

My main question would be: what tracking mount do you intend to use? The Sony sensors will be fine, but you will need to (probably) keep them pointed accurately for 180 to 300 secs to get good captures of deep sky objects and that takes a fairly solid mount. FWIW: I had a lot of fun with my old Sony NEX 5N getting into this hobby, but have now moved over to a cooled mono camera.

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Jonny Bravo

Jan 5, 2022

I'm not sure how much automation you're considering, but the Sony cameras don't play nicely with astro-imaging software like NINA, APT, etc. If you're just considering setting the camera/lens on a tracker or unguided goto mount, then you probably don't much care. However, if you want to get into plate solving, guiding, electronic auto focusers, etc… well, that Sony is not going to do you any favors.

Just food for thought.

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Astro-chicken

Topic starter

Jan 5, 2022

Andy Wray:
My main question would be: what tracking mount do you intend to use? The Sony sensors will be fine, but you will need to (probably) keep them pointed accurately for 180 to 300 secs to get good captures of deep sky objects and that takes a fairly solid mount. FWIW: I had a lot of fun with my old Sony NEX 5N getting into this hobby, but have now moved over to a cooled mono camera.

I am using an iOptron GEM28 mount. I've been really pleased with it performance thus far. I am using a ZWO120mm guide scope with PHD2 and am having no star trailing issues up to 4 minutes. I haven't tried longer yet.

Decent cooled mono cameras are within my budget BUT the major problem for me is I live the PNW and for half the year I get one or two nights a month to image so burning time on 3 filters just isn't reasonable for me. Jumping up to a decent cooled one shot color camera is a possibility but more money, I'd probably need to upgrade my imaging laptop, and its just more cables to deal with. The simplicity of a modded camera appeals to me more a this point than improved performance. Then again it's below freezing here from October to April so I already have a "cooled" camera for 7 months out of the year.

Astro-chicken

Topic starter

Jan 5, 2022

I'm not sure how much automation you're considering, but the Sony cameras don't play nicely with astro-imaging software like NINA, APT, etc. If you're just considering setting the camera/lens on a tracker or unguided goto mount, then you probably don't much care. However, if you want to get into plate solving, guiding, electronic auto focusers, etc... well, that Sony is not going to do you any favors.

Just food for thought.

Def not interested in any of that. I like the hands on of component. I have a go-to mount but don't use that feature as I enjoy "the hunt" as much as the photography side it. I have a separate guide scope that's doing all the communication with the mount using PHD2 for me so I don't need to tie in the Sony.

Jonny Bravo

Jan 5, 2022

I'm not sure how much automation you're considering, but the Sony cameras don't play nicely with astro-imaging software like NINA, APT, etc. If you're just considering setting the camera/lens on a tracker or unguided goto mount, then you probably don't much care. However, if you want to get into plate solving, guiding, electronic auto focusers, etc... well, that Sony is not going to do you any favors.

Just food for thought.

Def not interested in any of that. I like the hands on of component. I have a go-to mount but don't use that feature as I enjoy "the hunt" as much as the photography side it. I have a separate guide scope that's doing all the communication with the mount using PHD2 for me so I don't need to tie in the Sony.

Similar to how I started... after I upgraded from the Star Adventurer to a CEM40, I just ran my Lumix G9 with a 50-200 lens on it. I loved the ability to goto a target. Sure, hunting could be fun, but I realized I'd rather spend my time imaging a target than looking for a target

. It wasn't long before I bought a dedicated scope (the GT81) and added guiding. Now my setup is pretty much fully automated. 294MM Pro, EFW with LRGB and SHO filters, electronic focuser, scope-side computer...

Clear skies!

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Andy Wray

Jan 5, 2022 · Edited: Jan 5, 2022

Def not interested in any of that. I like the hands on of component. I have a go-to mount but don't use that feature as I enjoy "the hunt" as much as the photography side it

I was in exactly your boat and in fact had no way to control the Sony NEX-5N camera at all remotely (I had to use an infrared intervalometer to take pictures, manually focus using focus-peaking and had no live view). It was fun for a while, but soon wore off as the setup time and the long hours standing in the cold eventually took their toll. Being able to use sharpcap for fast polar alignment (you're probably already doing that with your guide camera) and then platesolving to get dead on target quickly (and repeatedly over several nights) is making a big difference to my experience ... more time capturing and less time setting up. The platesolving will probably be quite important for you if you have skies like mine where you only get a few hours a night every few weeks or so.

Ref the camera choice: The A6000 has almost exactly the same pixel size as a ZWO ASI1600MM Pro, so would be my choice (I may be biased as I moved from my Sony to the ZWO and wanted to retain roughly the same field of view and resolution). Also, your "seeing" may well be the limiting factor, so more megapixels doesn't necessarily mean better pictures.

Whilst I think about it: a 750mm F5 reflector like the Skywatcher 150 PDS would set you back less than $300, weighs only 5.5Kg and would work well with the A6000.

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daywalker

Jan 20, 2022

andrea tasselli:
Frankly, for the price of a used (and old tech) Sony A7/A7S plus the price of astro-modding it I'd go for a cooled CMOS dedicated camera instead. Note also the issue with the Sony firmware and the issue with its "star-eating" habit.

What he said.

I have ownded an AS7,and while i regret selling it, i would of never modded it for astro solely . Rather than curtail a good cameras ability into a niche id just buy a niche camera anway.

Good luck with whatever you decide though,ultimately you have to find your own way and im sure you will.