Fuji GFX lens for deep space astro

Started 9 months ago | Discussions
Richie S Contributing Member • Posts: 547
Fuji GFX lens for deep space astro

So I would like to be able to use my 50r to do some deep space Astro. I have a tracker and I’d like to add an fast lens in the “full frame” range of say 135 to 200. Not sure I’m ready to plunk down all that cash for the 250 and given I don’t need af I’m looking for a good telephoto to adapt. I have a Bronica sq 250, but it’s it’s an older version and frankly not the sharpest tool in the box - -so any nice alternatives that could fit the bill and offer full sensor coverage.

I’m doing this because of my youngest son’s love of space as I think it could give us some fun nights in the yard as the nights draw in.

Any options would be much appreciated.

JimKasson
MOD JimKasson Forum Pro • Posts: 33,865
Re: Fuji GFX lens for deep space astro

Richie S wrote:

So I would like to be able to use my 50r to do some deep space Astro. I have a tracker and I’d like to add an fast lens in the “full frame” range of say 135 to 200. Not sure I’m ready to plunk down all that cash for the 250

That's not a very fast lens.

and given I don’t need af I’m looking for a good telephoto to adapt. I have a Bronica sq 250, but it’s it’s an older version and frankly not the sharpest tool in the box - -so any nice alternatives that could fit the bill and offer full sensor coverage.

I’m doing this because of my youngest son’s love of space as I think it could give us some fun nights in the yard as the nights draw in.

Any options would be much appreciated.

Canon 200/2, but I don't know if it will cover. You might have to remove some baffles. If you're really interested, I can find out how close the Nikon 200/2 comes to covering.

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OP Richie S Contributing Member • Posts: 547
Re: Fuji GFX lens for deep space astro

Thanks Jim.

Having just scuttled off to eBay to check the 200 f2 I probably should have emphasized I am also looking for a relative bargain so likely in the manual focus focus, older lens category could be ideal here.

JimKasson
MOD JimKasson Forum Pro • Posts: 33,865
Re: Fuji GFX lens for deep space astro

Richie S wrote:

So I would like to be able to use my 50r to do some deep space Astro. I have a tracker and I’d like to add an fast lens in the “full frame” range of say 135 to 200. Not sure I’m ready to plunk down all that cash for the 250 and given I don’t need af I’m looking for a good telephoto to adapt. I have a Bronica sq 250, but it’s it’s an older version and frankly not the sharpest tool in the box - -so any nice alternatives that could fit the bill and offer full sensor coverage.

I’m doing this because of my youngest son’s love of space as I think it could give us some fun nights in the yard as the nights draw in.

Any options would be much appreciated.

Celestron 8 something? Or is that field too narrow?

Sorry, that’s a 42 mm image circle, and you need 55.

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tokyowalker Regular Member • Posts: 147
Re: Fuji GFX lens for deep space astro

Richie S wrote:

So I would like to be able to use my 50r to do some deep space Astro. I have a tracker and I’d like to add an fast lens in the “full frame” range of say 135 to 200. Not sure I’m ready to plunk down all that cash for the 250 and given I don’t need af I’m looking for a good telephoto to adapt. I have a Bronica sq 250, but it’s it’s an older version and frankly not the sharpest tool in the box - -so any nice alternatives that could fit the bill and offer full sensor coverage.

I’m doing this because of my youngest son’s love of space as I think it could give us some fun nights in the yard as the nights draw in.

Any options would be much appreciated.

Hi, Astrophotography is a whole different kettle of fish. It’s not necessarily how fast the lens is but more your location and the amount of light pollution. And how many times you are willing to sit there and take a photograph to integrate. Not to mention the accuracy in tracking. All that said you can get excellent results rather cheaply especially if you’re looking at wide sky rather than deeper objects.

Those fast prime lenses like 200/2 etc aren’t really practical at all IMHO because more importantly you need to put an H-Alpha filter on them to achieve any truly nice results, especially if you live in metro or suburban areas. Not only is the image circle small, they basically suck at the outer edges for astrophotography. In my opinion you’d be much better served by adapting a medium format telephoto lens with a sharp center and generous image circle. Manual focus. An -excellent- example is the Pentax SMC Pentax-M* 67 300mm F4 ED [IF] , + an 82mm filter. That rig with an adapter and good filter would perhaps cost $1000. That’s just an example. you could get away with a cheaper setup by going with an older lens and a 77mm filter. And actually you could use a 77mm filter on a larger lens as it doesn’t have such a negative effect on the final image - just reduces the effective aperture a bit. Filters are not cheap btw. I have a $550 77mm one but there are excellent filters in the $200 range.

if you want to see images from a particular device have a look at astrobin.com . A great forum for astrophotography is cloudynights.com .

You won’t find many images from a GFX50 though, simply because it’s a lot of sensor to cover. Pentax 645z is more common. Also keep in mind the GFX50 has a “35mm mode” which may help when you stack.

Personally I will try the GF 250 simply because it’s the next lens I’ll buy for terrestrial use. But I also have my eyes set on a Pentax 67 600/4. That lens requires a huge mount - $$$$$.

Edit: Below are a range of filters including a “starter Hoya” which is both economical and effective. The other 2 perhaps are in the higher budget range depending on your aspirations. I think a filter is your first step - you can get really nice shots even with a wide angle, as well as practicing your tracking.

https://www.amazon.com/Hoya-Starscape-Light-Pollution-Camera-Filter/dp/B082XLK5KB?th=1&psc=1

https://www.astronomik.com/en/filter-gegen-lichtverschmtzung-filters-against-lightpollution-lpr/astronomik-cls-filter.html?___store=en

https://www.highpointscientific.com/lumicon-82mm-night-sky-hydrogen-alpha-ha-filter-lf3115

Greg7579
Greg7579 Forum Pro • Posts: 13,518
Re: Fuji GFX lens for deep space astro

Very interesting.  I am driving 7 hours to Big Bend National Park sometime in the next three weeks.  It has the best dark skies in the US (so they say).

I have been there many times and shot the Milky Way, but only single shot usually around ISO 3200, 23 seconds F4 with the 23 mm.  Of course that is not enough light.  F4 just doesn't cut it.

I keep thinking I will try star-stacking and/or tracking.

I didn't know about those filters, but I don't need them in Big Bend for single shot astro right?

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Jvlahakis
Jvlahakis Senior Member • Posts: 1,019
Re: Fuji GFX lens for deep space astro

Greg,

Just came off of a shoot in the Finger Lakes region of upstate New York.  The astro pix were shot with the GFX 100 + 23mm at iso 1600 30 seconds.  No filters.  I'm going to guess that Big Bend will have clearer darker skies than what I experienced.  I shot my pix in aperture mode.  Big Bend is on my list to get to hopefully before year's end.

Best,

John

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tokyowalker Regular Member • Posts: 147
Re: Fuji GFX lens for deep space astro

Greg7579 wrote:

Very interesting. I am driving 7 hours to Big Bend National Park sometime in the next three weeks. It has the best dark skies in the US (so they say).

I have been there many times and shot the Milky Way, but only single shot usually around ISO 3200, 23 seconds F4 with the 23 mm. Of course that is not enough light. F4 just doesn't cut it.

I keep thinking I will try star-stacking and/or tracking.

I didn't know about those filters, but I don't need them in Big Bend for single shot astro right?

https://www.darksitefinder.com/maps/world.html#6/32.222/-104.293

You won’t need a filter for there if you can find a place in a field etc not bloomed by a street light. Like a field etc.

Have a look at the map. I don’t know specifically where Big Bend is but I guarantee it’s a helluva lot better than Tokyo.

You can surely get away with wide stuff like the Milky Way etc without tracking. If you use a longer FL and want pinpoint stars you’ll need a “sky tracker “ or an equatorial mount.

In astrophotography F4 is considered very fast btw 😉 Generally a series of short exposure images are taken while tracking and stacked along with a dark and a flat frame for integration to remove noise. Most Fujifilm’s use X-Trans so RAW support in processing is mostly missing but you can convert to TIFF or DNG and it works fine. Even though the GFX is Bayer native Fujifilm raw support is missing in general. Check out :

Free software for stacking:

http://deepskystacker.free.fr/english/index.html

A nice list of software resources:

https://www.spaceoddities.eu/2018/11/the-best-resources-for-astrophotography/

Not to mention DPReview has an astrophotography forum of course which I think is more focused on DSLR astrophotography.

if you go to Big Bend in winter you’ll of course see some amazing (and rare) skies at night.

Using a telephoto camera lens & DSLR is an awesome capability that’s a very recent development, and very common. When I started in digital astrophotography I had to build my own Peltier cooled camera using a Texas Instruments CCD. Then attached to the telescope. I have a cooled camera and nice fast scope now (Celestron RASA 400mm F2), but that’s a finicky dedicated setup. I’m looking forward to using the GFX50s because the resultant files can produce nice HUGE prints. More so with the GFX100.

BTW to get an image circle covering a GFX sensor at F4 in a true telescope design would cost >$8,000. So MF lenses are a great compromise.

Good luck & Clear skies. Hope to see your Astro pics soon. I’m cloud bound until December around here,

Edit: Actually if I were traveling 7 hours I’d gamble on at least one or two filters. Like a Hoya RA54. You may be in a place least affected by man made lighting but it’s still present in the upper atmosphere, not to mention natural radiation.

Greg7579
Greg7579 Forum Pro • Posts: 13,518
Re: Fuji GFX lens for deep space astro

I was in Big Bend last Dec with the 23 mm F4 and GFX 100. I shot a bunch of single shot astro. This one was 20 seconds at F4, 2000 ISO. I had to export it at 70% quality jpeg i  LR to get it down to 50 MB so I could post it here. I think F4 is too slow for astro single shot.

On the raw at 100%, you can see star trails even at 20 seconds.

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tokyowalker Regular Member • Posts: 147
Re: Fuji GFX lens for deep space astro

Greg7579 wrote:

I was in Big Bend last Dec with the 23 mm F4 and GFX 100. I shot a bunch of single shot astro. This one was 20 seconds at F4, 2000 ISO. I had to export it at 70% quality jpeg i LR to get it down to 50 MB so I could post it here. I think F4 is too slow for astro single shot.

On the raw at 100%, you can see star trails even at 20 seconds.

Without moving the camera synchronized with the stellar body you’re working against the laws of physics to get round stars no matter how short the exposure. The flip side to that is that then you then introduce movement into the landscape.

OP Richie S Contributing Member • Posts: 547
Re: Fuji GFX lens for deep space astro

I do love the skies in the Chisos basin and up on the south rim trail. Ironically I’ve seen more impressive night skies in Shenandoah np though.

Right now I think I need to find my feet in the back yard and when I get a bit more confidence I’ll try to track down some darker spots. I’m not bad where I am for light, there are no street lights in and if I turn all my outside lights off it’s pretty good.

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