How big of a difference will a few F-stops make at night?

[AXIS]

Im considering picking up a 35mm F1.8 as the start of my lens collection (so far its just the 18-55mm kit).
I really want to shoot more night shots, especially astrophotography type of stuff.

Is the change from F3.5 (well, F5 at 35mm) to F1.8 going to be a huge difference for night shots or will I notice much of a difference at my amateur level?
I tried taking some shots of the stars the other night and some turned out ok. Id really like to get some better shots but I dont know if the lens is going to make that big of a difference or not.

 

[OfMikeandMen]

It will allow you to shoot nearly 2 full stops faster, I believe. In other words, if you had to shoot at 1/60 @ f/3.5, you could shoot close to 1/250 @ 1.8 (it's 4x faster). Correct me if I'm wrong. The difference is significant, though. If it's the Nikon lens, I've used it. It's a great lens. But if you want some better bokeh, I've heard the 30mm 1.4 sigma is better (and it'll get you faster speed for $200 more -- but Nikon trumps in sharpness).

However, for astrophotography you'll need a tripod and run it on bulb mode, so speed won't REALLY be your concern, but you will need the additional light. You also might want to look into something like a 50mm lens, if that's the case. But don't quote me. IDK much about it.

 

[AXIS]

The one thought I had was that since I will be shooting on a tripod and not using an equatorial mount than the aperture should allow for some better shots before star trails start to develop.
I plan on using it as more of an all around lens but one of my interests is definitely the stars.

Ive been debating back and forth about the 35mm or the 50mm still. Idk which I will go with if I do purchase one.

 

[Judobreaker]

Personally I think the 35mm would make for more interesting shots than the 50mm when it comes to stars.
When shooting stars I would either use a wider lens to get a nice wide starry sky (possibly with surroundings included) or a longer lens for more detailed shots.

This is still personal taste of course. ^^

 

[Judobreaker]

It will allow you to shoot nearly 2 full stops faster, I believe. In other words, if you had to shoot at 1/60 @ f/3.5, you could shoot close to 1/250 @ 1.8 (it's 4x faster). Correct me if I'm wrong. The difference is significant, though. If it's the Nikon lens, I've used it. It's a great lens. But if you want some better bokeh, I've heard the 30mm 1.4 sigma is better (and it'll get you faster speed for $200 more -- but Nikon trumps in sharpness).

However, for astrophotography you'll need a tripod and run it on bulb mode, so speed won't REALLY be your concern, but you will need the additional light. You also might want to look into something like a 50mm lens, if that's the case. But don't quote me. IDK much about it.

Speed is a concern if you want to avoid star trails, the faster a shot is the less stars trail.
Also, the more you zoom in the less time is needed for stars to start trailing so a 35mm would also make it easier to avoid trailing then a 50mm for example.

 

[tirediron]

It will allow you to shoot nearly 2 full stops faster, I believe. In other words, if you had to shoot at 1/60 @ f/3.5, you could shoot close to 1/250 @ 1.8 (it's 4x faster). Correct me if I'm wrong.

You are correct that the 1.8 is approximately two stops faster, but you have to factor in the aperture, so, therefore, if we leave the shutter-speed constant at 1/60, we see that when we go from f3.5 to f2.5 (approx. 1 stop) we've double the amount of light, and when we go the next stop from f2.5 to f1.8 (1.7 would actually be a full stop, but, close enough) we've doubled again allowing four times the amount or two stops of light. Conversely, the f3.5 lens, which can only shoot at 1/60 wide open is trumped by the 1.8 lens which can shoot at 1/250 wide open. You can get one two stops of shutter speed, two stops of aperture, or one stop of each, but you CANNOT get two stops of each.

 

[amolitor]

With the high ISOs available on modern cameras, the f/1.8 lens can pretty much see in the dark. The kit lens.. can't. It will make a gigantic difference to you, in practical terms.

 

[KmH]

The OP notes the 18-55 mm kit lens is at f/5 when zoomed to 35 mm.

F/5 to f/1.8 is 3 stops.

Nikon's AF-S 35 mm f.1.8G DX has issues when used at or near f/1.8
• soft focus
• low contrast
• lateral chromatic aberration
• purple fringing
• bokeh chromatic aberration

Which is why the lens is inexpensive.

So to get nice sharp images and to minimize the issues the lens has near wide open it needs to be stopped down to somewhere in the range of f/3.5 to f/14.

 

[gsgary]

You don't need a fast lens to shoot stars

 

[OfMikeandMen]

Thanks for correcting me, those who did I learn so much here!

 

[runnah]

Buy a remote shutter release and any lens will shoot at night.

When I do night shots I crank the ap up to f/7.1 to get night crisp focus and use a 2 min exposure. Plus I have the ISO way low to get noise free images.

 

[CaptainNapalm]

It will be a difference but nothing that will blow you away. Besides, it likely won't be in your best interest to shoot a sky full of stars at aperture 1.8. My best night shots are when using a tripod, ISO=100 and a long exposure.