notBert Loc: Ft. Collins, Colorado

I prefer using zoom lenses and I am trying to decide between a Sony 10-18mm f4 & Tamron 11-20mm f2.8 for occasional Milky Way fotos which include foregrounds. At 88 yo I appreciate Sony's OSS on my 200-600mm telefoto lens for birding. So I think Sony's 16-20 is worth the 1 stop decrease as the Tamron is w/o OSS as is my Sony A6300 camera. Either lens will be used mostly for landscapes, etc.
But I am curious as to which is better for astro-fotos? TIA

Sidwalkastronomy Loc: New Jersey Shore

I have a Tamron 10-24 on a rebel crop sensor camera and love it. Nice range and sharp enough for me. I going to use my lens for star shots also when I don't have one of my scopes

imagemeister Loc: mid east Florida

The faster lens is what you want OSS is irrelevant ........
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bwana Loc: Bergen, Alberta, Canada

I use the same lens with adapter on all my Sony mirrorless bodies. Although it is designed for a crop mode camera it works nicely from ~14-24mm on a full frame sensor. f/3.5-4.5 is fast enough for wide field astro-imaging.

bwa

notBert Loc: Ft. Collins, Colorado

Thanx bwa. I am still leaning towards the Sony f4 w/ OSS for other than astro-pics which are on tripod or EQ mount. Good to hear that f/ 3.5to4.5 is adequate for exposure. Is that for a single shot or long exposure w/tracking? Obviously I am a novice @ this!

bwana Loc: Bergen, Alberta, Canada

I primarily use the 10-24mm lens for Aurora imaging. 10 sec. subs @ ISO 1600, tripod mounted.

Using the 500 rule for exposure (exposure in seconds=500/focal length), I can push exposures at 24mm to about 20 sec. for Milky Way imaging off a tripod with minimal star trailing. Of course, with a tracking mount the exposure is essentially unlimited depending upon the accuracy of your tracking.

bwa

notBert Loc: Ft. Collins, Colorado

Thanx, once more. I am in the midst of my semiannual commute to Colorado and will not decide until I return, meanwhile here in Florida I just bought a Sony 70-350 f 4.5-6.3 for moon, bird & moose, etc fotos. I am trying to put together one of those flip animation cartoon like mini-books for my great great grandson who was fascinated by clips I seńt of full moon and waning, but it is slow going as clouds, etc do not make for shoots every day of the ~ 28 day cycle. Also, after New moon after sunseet when its magnitude goes from -4.8 on 1 May to -9.3 on the 6th is most challenging. I know about the looney f/11 rule, which works around full moon nites, tho my A6300 spot reading works @ -2stops compensation to tame hilites w/ bracketing usuallly 5 exposures @ ½stop intervals. Crescents are not that easy being spot is too large. I once asked this group if anyone knew how to calculate shutter speed (say @ f stop @8 at ISO 800)to no avail. There is an app Photographer's Companion which suggests exposurs,, but my French is nil and not sure where to send question how calculated. Do you have any better ideas? TIA

mikeroetex Loc: Lafayette, LA

OSS won’t matter for astrophotos, as you will have it turned off and camera mounted on tripod.
Go for the lowest aperture lense you can afford. I find 11-16mm at 1.8 or 2.8 to be a sweet spot.

imagemeister Loc: mid east Florida

This is what I have been saying .......

JimH123 Loc: Morgan Hill, CA

Probably should add that not all fast lenses are suitable for astrophotography. Some have so much coma and astigmatism distortion, that they just don't make pleasing results.

And the price of a lens is not usually a very good indicator of how well they will do with stars. Stars are point sources of light and really test a lens.

A good source of information can be found at lonelyspeck.com. And this page goes into what their lens recommendations are: https://www.lonelyspeck.com/lenses-for-milky-way-photography/

And here is a spreadsheet on lenses they have put together: https://docs.google.com/spreadsheets/d/1p8FSEIaDd45i97NXFEZf4fnVOQ3ifA43ecJcuS0nCJ0/edit#gid=2

Also on the site, if I search for "best lenses", there are many more matches:
https://www.lonelyspeck.com/?s=best+lenses

Some lenses I have used with good results are: Tamron 15-30mm f2.8, Rokinon 24mm f1.3, Rokinon 14mm f2.8

It also makes sense to do a panorama of the Milky Way. The result produces a wide angle of view, but done with a longer focal length which actually produces a form of super resolution. Individual stars turn out smaller and distortion effects are not as pronounced. Also, the panorama will favor the center portions of each image where the stars are sharper and discard to edges and corners where the worst looking star are found.

Attached is a sample single image (non-panorama) using the Rokinon 24mm f1.4 lens. It was also mounted on an Olympus EM5ii which is m4/3. With the 2x crop factor, only the center portion of the lens is being used and this image shows how stars have been rendered. Note: There are reports that not all Rokinon lenses produce these results and there is evidence that manufacturing is not consistent.

The 2nd sample is the Tamron 15-30mm f2.8 adapted to the Olympus EM5ii, and taken at 15mm. Again notice how well the stars are formed.

I could also show examples with lenses that don't work as well.

sample using Rokinon 14mm f1.4 on Olympus EM5ii

(Download)

sample using Tamron 15-30mm f2.8 w Olympus EM5ii

(Download)

notBert Loc: Ft. Collins, Colorado

THANK YOU, Jim for a detailed & informative reply.
AND for the link to Ian Norman's website. It is a treasure trove. His article on Star Trail Calculator is worth my donating. I love that he took the time to detail its working replete w/ the math so now I can build my own spread sheet for this Fon. I plan to ask him to help w/ my Star Magnitude/Exposure dilemma.
I am putting off the Tamron vs Sony wide zoom til after return to Colorado.

notBert Loc: Ft. Collins, Colorado

THANK YOU, Jim for a detailed & informative reply.
AND for the link to Ian Norman's website. It is a treasure trove. His article on Star Trail Calculator is worth a donation. I love that he took the time to detail its working replete w/ the math so now I can build my own spread sheet for this Fon. I plan to ask him to help w/ my Star Magnitude/Exposure dilemma.
I am putting off the Tamron vs Sony wide zoom til after return to Colorado. I have discovered from my days as a film fotografer several Olympus Zuiko lenses (16mm rectilinear 3.5, 24mm 2.8, 40mm 2, as well as 35mm 2 Nikkor & 60mm 2.8 macro Nikkor) which once I complete great great grandson's animation may along w/ Lonely Speck tutorials to try Milky Way & Orion shoots.
Again thank you so much. My summer nites are going to be full of new experiences. I may even clean the mirror of my C-5 Schmidt Cassegrain. I wonder if I can do a panorama using its FOV in arc-minutes to take a series of overlapping shots a stitch them togethr? WhaddaYaThink??
Ernie (notBert), my 3 sons loved Sesame St!

JimH123 Loc: Morgan Hill, CA

In looking at your equipment, I see you have the Sony A6300. I have that camera, and I have the Sony 10-18mm f4 lens. I haven't yet tried it for Stars. Next clear night I get, I will give it a try and see what it can do.

Here is another hint. Many lenses have a CA problem where the different colors don't come together at the same point. It is possible to use colored filters to limit which colors the sensor sees, and in many cases, the CA problem disappears. But then, it is necessary to turn the image into B&W also. Green also works well, and since the camera has more green filtered pixels than red or blue, it works well.

My A6300 has been modified to be a mono sensor by the removal of the color filter array. I just love the camera being a mono sensor. If I want color, I have the A6600.

Two years ago, Comet Neowise was in our night sky. The first image is that comet using the A6300 along with a small telescope, the AstroTech AT60ED. I tend to have more fun using shorter focal lengths, and this scope is 360mm at f6. I use a field flattener with it.

First image is Comet Neowise with the A6300 and this AstroTech scope.

Second image is using an Olympus EM1ii with the Olympus 12-100mm at 100mm.

A6300 and AstroTech AT60ED

(Download)

Olympus EM1ii and Olympus 12-100mm f4 - using stacking

(Download)

notBert Loc: Ft. Collins, Colorado

I just typed a rather long reply buTT Nature called & when I returned had lost the page looking for Jup/Sat foto AND now can't get back to original msg.
Is ther a way to save an incolete msg on UHH & return to it later? Or need I type all in Libre Word Processor to Cut&Paste?? TIA

JimH123 Loc: Morgan Hill, CA

I know of no way to save an incomplete msg to be finished later. Cut and paste would work.

I intend to try out the Sony 10-18 for stars, but have only had cloudy nights lately.