Astrophotography R5 - Sigma 14mm f/1.8 Art or RF 15-35 f2.8?

I did my first night shooting on Sunday night from 10-1 AM, the workshop was not on astrophotography, we did get some night sky in our shots. Here is a post on the workshop.

https://photography-on-the.net …/showthread.php​?t=1525178

My challenge during the workshop was my lens. I had the slowest lens in the group. Most were shooting wide f1.8 and f2.8 lenses (Sony and Nikon). I have wanted to do more night photography and the workshop gave me some new ideas to try. I also have been wanting to do some astrophotography. I live in an area that I can drive to some very nice dark sky locations with in a few hours.

When I first heard about the RF 16 f2.8 I thought this would be a great lens to start with for some night shooting, but while the results and reviews I have seen are not bad. I have also read enough reviews of night shooting with the lens that I don't think this is the lens for me. Right now I am looking at two lenses. The Sigma 14mm f/1.8 DG HSM Art (adapted) has been recommended by several R6/R5 night shooters. The images I have seen are very nice. I am also considering the RF 15-35 f2.8. My main concern is the speed for astrophotography. But after the results I was able to get at the workshop with an f4 lens I am wondering if the f2.8 might be fast enough with an R5. Plus, the lens would be very useful for other types of shooting.

Is anyone using either or both of these lenses for night shooting. Any recommendations for these or other lenses. I want a lens that is going to deliver shots if I am going to stay up late and in all types of conditions.

Hi,

Speed is one part of this. Coma is the other. Personally I don't care how fast a lens is if it's coma is horrible with oblong seagull stars in most of the field of view except the center. So when evaluating a lens, I would suggest you really look at that performance too. The faster the focal-ratio the smaller the coma free field will be and these ultrawides are just always going to have heavy coma issues due to optical physics without correcting lenses for it (which exist, but not for terrestrial lenses like camera lenses). So just look for examples of a wide field sky shot with any lens you're looking for and look at the star shapes from center to corners to get an idea of how bad the coma is. The zooms will be even worse than a prime in this regard too. If you don't care about seagull star shapes, then just get whatever you like that is fast.

Very best,

One of the things you'll lose with the Sigma 14mm f1.8 is the ability to zoom in on the part of the sky you're interested in. This shot is a JPG SOOC made with that Sigma where I was trying to capture Orion. There's so much in the shot that Orion's pretty much lost.

Thanks for the responses. I really would prefer the RF 15-35 for several reasons. One is the size and weight, the Sigma is a big heavy piece of glass and I will still need to add an adapter. Another reason is the flexibility of a zoom as you mentioned. A few other reasons, I could use the lens as my standard wide angle and sell my 16-35 f4 to help fund the purchase. This would pretty much make up the difference in price. Just worried if f2.8 is going to be too slow. Although I am very impressed with the high ISO I used on my night shots from last week.

if you ever shoot astro with a fast lens you'd have a hard time settling for f2.8. when i shoot astro i only carry one lens, the sigma 14 f1.8, so the weight isn't an issue.

ed rader wrote in post #19357751
if you ever shoot astro with a fast lens you'd have a hard time settling for f2.8. when i shoot astro i only carry one lens, the sigma 14 f1.8, so the weight isn't an issue.

Hi Ed,

Thanks for your response. I have started leaning towards the Sigma 14 f1.8. I am pretty sure this is the right way to go for astrophotography. Just wish they had a native RF version. But I have several adapter so it should be find. I appreciate your willingness to share your advice. BTW, your gallery is great!

Hi Ed & Everyone,

Thanks for the suggestions. I found a great used Sigma 14 f1.8 at B&H for a great price. The lens was listed at 9+, but arrived today and I can't see a mark on the lens, looks like new. Hopefully this weekend will be clear in Central Utah and Northern AZ. Already creating a plan using the Photo Pills app. Great app for astrophotography.

Due to the used cost I was able to buy the lens outright. I had been planning a trade + cash with MPB for a RF 15-35 f2.8. I might still do a trade later. If the Sigma lens works out, I might trade for a RF 14-35 f4 instead.