Some DSLR lens data for astrophotography

[gregbradley]

I thought I would list the lens I have or know of that are useful or not for astro work. I use Nikon, Fuji and Sony cameras. I have an olde Canon 40D so my knowledge of Canon lenses is limited.

I have a Pentax 67 55mm F4 lens that is fairly poor unless used 2x2 binning. With my Proline it was shocking until I stopped it down to about F5.6 and 2x2 binning and it cleaned up.

Samyang 24mm F1.4 cleans up at F2 and so does coma.
Samyang 8mm F2.8 fisheye for Sony - awesome lens, perfect wide open, only $280 and super sharp. Fisheye effect is not for everyone though.
Nikon 85mm F1.8g cleans up around F2.2 ($650 lens)
Nikon 180mm F2.8 is not bad wide open (unusual - probably because it has ED glass in it) (about $400 2nd hand)
Contax G 90mm Zeiss Sonnar seemed clean wide open (on a Sony Nex 6)
(this is a superb lens). APSc lens needs an adapter $70, $300 lens 2nd hand there is also a 45mm F2 ($450 reputed to be one of the sharpest lenses around - I have one and haven't tested it yet) and a 28mm F2.8 ($450) and 21mm F2.8 ($900)
Pentax 165mm 67 F2.8 is clean wide open (a little bit of blue haloing easy to clean) $200 2nd hand - a great buy 85mm of backfocus
Nikon 50mm F1.8g is pretty clean and clean and coma free by F2.2 ($200 lens)
Nikon 24-70 F2.8 is clean from wide open and no chromatic aberration - very nice ($2100 lens)
Nikon 14-24mm is clean wide open $2100 lens)
Nikon 105mm F2.5 is clean F2.8 onwards (cheap lens but high quality). (About $200)
Nikon 28mm F2.8 AIS is a cheap lens but super sharp and has quite a reputation. I think its clean wide open. ($250)
Nikon 55mm F2.8 micro - no good, sharp for macro shots. ($89)
Canon 50mm F1.8 seemed identical to Nikon's 50mm F1.8D but perhaps not as good as Nikon 50mm F1.8g which is a very good 50mm lens and cheap new ($140 or less).
Canon FD 85mm F1.4 lots of CA and cleans up around F4 ($100)
Canon FD200mm not too bad but needs F4 ($300)
Canon FD 55mm not so useful.($100)

Don't know as much about the Canons but usually Nikon/Canon match each other fairly closely with some exceptions so I would expect similar with the Canons. The 50mms are usually good value at under $200 for both brands.

Minolta Rokkor get good reviews and they are cheapish 2nd hand.

So do Pen F, Zuiko, Voigtlander lenses, some Olympus lenses 2nd hand from about $80 to about $600 usually shorter focal length are more expensive).

As autofocus isnt't really used then legacy lenses with adapters makes a lot of sense for high quality low cost lenses.

For Fuji X system 35mm F1.4, 14mm F2.8 are superb lenses. Fuji lenses are about as good as they get and probably similar or not far behind Zeiss lenses. The 14mm F2.8 is better than my Nikon 14-24mm F2.8 but of course its for APS cameras and specifically only Fuji as the flange to focal plane distance is quite small and won't fit on DSLRs as the mirror gets in the road.

But Fuj XE1 and Sony Nex 5 and 6 are very workable Astro cameras for nightscapes so don't feel you are limited to Canon or Nikon. Olympus OMD EM5 is also.

Of the 2 the Fuji is a bit better at high ISO low noise than the Sony Nex 6 but there isn't a lot in it and long exposure noise reduction on each narrows the gap even more. Fuji XE1 and Nex 6 would outperform any Canon except 5D3 and 6D but again its limitation is APS size.


Greg.

[Joshua Bunn]

Thankyou Greg for sharing your experiences here, there is some great info in there.
Josh

[multiweb]

Yeah thanks for the info Greg. That 67 Pentax 165mm is starting to look real good. Checked a few on eBay. Cheap as chips. :thumbsup:

[astroboy]

Great run down on some excellent lenses Greg , I'll be looking forward to hearing about the Zeiss 45mm .
A couple to add to the list
nikkor 85mm F2 excellent at 2.8 ( old AI )
nikkor 50mm F2 also excellent at 2.8 ( also old AI )
One thing I noticed about Micros wide open they are often sharp but Vignette badly so the Nikkor 105 F2.8 Micro is very good at F4
You have me tempted with your thoughts on the Fuji , I use a X100 now and love it and trying to justify the X1 Pro or the XE-1
Any thoughts on which is the better camera.

Thanks
zane

[gregbradley]

Its got a lot going for it. 85mm or so backfocus makes it easy to handle with filter wheels etc. Its quite sharp and is clean wide open. I like it a lot.
Its also very nice as a terrestial lens with nice bokeh and easy to use focus ring. Adapters are cheap as chips on Ebay. The 55mm Pentax though is not as good but pretty good binned 2x2 as seen here:

http://www.pbase.com/gregbradley/image/140884665

Of course the cream of the Pentax is the 67 300mm F4 EDIF. Phil Hart won Malins last year with a shot using one of those and I am sure we all remember Marco Lorenzi's stunning widefield shots with that one. Kind of rare and expensive, it often sells for US$1950 on Ebay and does not come up much. The cheaper and more plentiful 300mm F4 (non-ED) sells for around $450 or so and is also sharp.I haven't used mine much but as I recall it was coma free wide open (F4 though). I think it would be good for narrowband widefield.

Greg.

[gregbradley]

The Contax g Zeiss 45mm F2 is regarded as one of the sharpest lenses anywhere. I have only started using it on my Fuji XE1 and Sony Nex 6.
Its beautiful. I was so amazed by the performance of the 90mm Sonnar that I could see why people rave about their Zeiss lenses. I could be hooked. Its like using a Takahashi scope for the first time! Too bad its only manual. But there is a Taiwanese guy who has invented an adapter that allows AF with Contax g lenses. Its $300 and only for Sony Nex for You can rotate the dial to get up to 10X. So manual focusing is not that hard.

Of course the downside to Contax G lenses is they are limited to mirrorless. You also have to be careful of the 21mm as the rear lens element is close the sensor. There are some reports of filing down the rear metal flange. No problem with the 45mm. You can't use them on your DSLR. There are Contax Yashica Zeiss lenses that I think will fit DSLRs (not 100% sure though).

As far as XE1 versus XPro 1 I think that is pretty easy. The XE1 came out later. They are identical except XE1 has a worse LCD but much better EVF and XPro has a hybrid viewfinder (both optical and evf). XPro 1 is larger and more expensive. But sensor, menus, everything is the same. XE1 has a remote port for an intervalometer - XPro 1 does not so be careful there. You may be unable to use XPro 1 for time lapse.

An XPro 2 is slated for later this year. No doubt it would at a minimum have the X100s improvements which have received enthusiastic reports.

XE1 is quite clean at ISO6400 but Fuji does overstate their ISO by at least 1/3rd of a stop so its really only ISO5000+ not ISO6400. Sony Nex 6 is a tight competitor for XE1 and in some ways is better suited for astrowork.
It has a tilt screen, same sensor except the latest version with on chip PDAF autofocusing (same as X100s), focus peaking ( a colour fringe appears in viewfinder when you have maximum sharp focus - very nice to use),
wifi (perhaps a bit of a gimmick but you can control it from iphone, not set anything but simply fire off a shot), gps (again not important to me), more importantly for me was there is a time lapse app you can buy for $10.

I have used it. Its nowhere near as friendly as the Nikon which is sooo nicely implemented. But I "think" it works. The last time I used it I did manage to do a time lapse but when played back on the camera it seemed way too gappy. Not sure why, all the settings were correct. Its not very user friendly but I think once you master it the good news is it stays at your last settings so it would be fast to operate next time.

XE1 and Nex 6 are almost as clean as my Nikon D800E. But full frame of course still has the edge.

XE1 video is only so so. Perhaps even poorish. Sound is poor. Nex on the hand is superb with great clear stereo sound and non distracting AF as well as power zoom and stabilisation so your videos look like they were taken on a stabilising video mount.

You can also get a Metabones speed booster to up the cheap legacy lenses in F ratio speed. Same as a reducer on a telescope. There is one available for Nex 6. I was looking at getting one when they had the right type for me (lots of models). This is supposed to make your APS sensor perform the same as a full frame. It gets good reviews. They start at US$399 and go up to $599 depending on the model.

Most simply get a Canon to do their astrowork and they are great cameras. But I don't think Canon has anything in APS size that can match Fuji and Sony. Exmor sensors rule and are ahead of everyone at this stage (the scene is always changing but they have a significant lead. Toshiba have a high QE sensor in the Nikon D5200 but apparently it can band in shadows like 5D2). Basically Exmor sensors retain high dynamic range and have very good high ISO performance, are light (very good for Polarie), lenses are cheaper and are aimed also at users of legacy lenses with good manual focus facilities (mainly Nex but XE1 is useable that way for sure).

Greg.

[astroboy]

Thanks Greg
As always you have given me a lot of food for thought.

Z

[tilbrook@rbe.ne]

Thanks Greg!

That's a very useful list.
Good to have your experience.

Cheers,

Justin.

[gregbradley]

Some examples of Zeiss 45 and 90mm Contax g lenses on Fuji XE1:

http://www.pbase.com/image/149959178 Zeiss 90mm Sonnar (Contax g Fuji XE1)
http://www.pbase.com/gregbradley/image/149956797 same scene Zeiss 45mm F2.0 (Contax g and Fuji XE1)
http://www.pbase.com/gregbradley/image/149959214 Zeiss 45mm F2 (Contax g Fuji XE1)
http://www.pbase.com/gregbradley/image/149956783 Zeiss 90mm Sonnar (Contax g and Fuji XE1)

I have some nightscape shots with Zeiss 90mm and also Samyang 8mm fisheye I'll post soon.

Greg.


Greg.

[Retrograde]

Just want to add my thanks to Greg for this thread. This is a great resource for those of us looking to acquire some lenses for astrophotography.

[iceman]

Worth adding the Samyang / Rokinon 14mm, f/2.8.

Great even wide open, $400. Comes in Canon, Nikon and Sigma mount.

Has some mustache distortion, but is easily corrected with the right lens profile.

[jjjnettie]

Isn't it funny, I was researching this last night. :)

I'd like to add another lens to the list.

Tamron 90mm f/2.8 SP Di macro

For me it's the ultimate dual purpose lens. Not only does it take superb sharp macros, it's a cracker for wide field astro work.
As usual, it needs to be stopped down a little. But that is the norm using lenses at night. Just like a telescope, they work best at F4 and up.

In my reading last night, it was recommended to stop it down using an aperture mask instead of "in camera". Apparently it sharpens the stars up more as there is less diffraction from the aperture blades. Will have to give it a go. :)

[Wavytone]

Hi jjjnettie,

By all means try placing an aperture stop in front of the lens, but take a close look at the stars in your images afterwards because you may find it causes a few issues:

a) it almost certainly will produce vignetting (dark corners)
b) it may make coma worse for off-axis stars, and
c) it may make lateral colour aberrations worse (ie stars are stretched into radial coloured streaks).

[Steffen]

I agree, anything intruding into the aperture in front of the lens will cause vignetting (except with telephoto lenses).

I know that hexagonal iris apertures will cause diffraction spikes but I don't think it will affect overall sharpness much. If the diffraction spikes are unwanted then rounded many-blade aperture irises should be used. Unfortunately, great glass and a round aperture don't always come in the same lens… :(

Cheers
Steffen.

[trek1701]

Hi Mike

Could you please elaborate to a novice such as myself on the meaning of "with the right lens profile" for the Samyang lens on a Canon canera?

Thanks Mark

[gregbradley]

Lightroom, Canon DDP, Nikon View NX2 have lens profiles. Some cameras will do lens corrections in their internal firmware. Lightroom and others detect the lens used in the exif data when uploading or you can select what lens you used when developing your image. They have a list. The lens corrections needed to counteract distortion are already worked out.

That makes it easier. Otherwise there is a manual slider for it and you can also do it in Photoshop under Filter/Distort/Lens Corrections.

You can correct for vignetting (easiest thing to correct for) and distortion.

For a fisheye there are software programs that will de-fisheye the image distortion. I think DXO have one. DXO make a stand alone program for this lens correction work.

As far as the aperture iris causing different diffractions that is also an item that is noted in many lens reviews. Sometimes they are referred to as sunstars which is the diffraction spikes produced by a lens taking an image of the sun.

Some have 9 blade apertures, some 8 etc. Some are rounded others are hexaonal. Rounded ones would be best. Fuji's are rounded for example.

Greg.

[gregbradley]

Out of interest I posted what would be a good legacy lens for a Sony Nex 6 (APSc 16.1 mp Exmor sensor lightweight camera - $815).

Here are the responses I got:

•Sigma 8-16mm (manual focus on LA-EA1)
•Mamiya/Sekor 55mm f/1.4
•Tamron SP Macro 90mm f/2.5
•Minolta AF D 75-300mm f/4.5-5.6 (on LA-EA2)

Minolta MD Rokkor-X 50mm f1.4
E mount SEL 35/1.8, then 10-18mm/4 and Olympus OM 100/2
On a Nex-6, I would rank these lenses by achievable IQ:
1.RF: Contax G, Zeiss ZM, even Voigtlander (ignoring Leica) all deliver stunning IQ
2.E-mount: SEL24F18Z
3.E-mount: Sigma 30
4.E-mount: SEL35F18 OSS and SEL50F18 OSS
5.A-mount: prime lenses (A35, A50, A85)
6.E-mount: Sigma 19 (and likely SEL20F28)
7.Legacy: Olympus OM, Minolta MD, Nikon AFi, Canon FDn prime lenses
8.Zoom: SEL18200 OSS
9.Zoom SEL1650P OSS or SEL1855 OSS

Sizewise - Summicron 40mm F2

Nex native lens - 24F18

Legacy lens - Elmarit 60mm

Alpha mount - Sigma 24-70

Price with performance - FD 70-150 f3.5
Leitz Macro-Elmarit-R 60mm 1:2.8
Viogtlander 21mm F4 colour scopar

The Voigtlander is F4 but it may still be good as it probably is good wideopen.

Greg.