Photographing the Perseids (or any meteor shower)

[DeutschBag]

Hey all - any advice on doing this? I'm lazy and didn't feel like wading through a bunch of past threads. I found some ambivalent advice online (low f-stop vs high, low iso vs high, etc...)

I took a few test shots last night - and they came out shitty. Think I shot the below at f2.8 iso 100. Lots of ambient light from the city to the south, but that's going to be hard to escape in overly-dense Germany. I read something about using a higher f-stop and high iso (800-1600) in order to reduce some sort of thermal signature that makes the stars look blurry and blobby. See my north star below for example and how it does not look like a point - is this due to the f2.8 and iso100 settings? Will shooting on the higher settings help? I'm not very mobile right now, so I'm just trying to look for an easy way to take some decent photos. I have a nice RF remote that is working great, so that will help. Compose the shot while it's still a bit light out, then wait for the show at around 1am. That's the plan at least. Now, if it will only stay clear. That's asking a lot from the land of the nearly non-existant summer.

[Fuzz]

On your shot, Polaris looks like a blob for two reasons. First is that Polaris isn't exactly due north -- it does move, so you will see it making a revolution (albeit a small one). Second is that it's in the corner, which is typically where lens weaknesses show up (obviously worst at the widest aperture) -- so some of the smearing is due to that as well.

Aperture: don't want to use lens at widest aperture since it's usually the softest -- want to stop down slightly, but not too much that the faint meteors won't show up. Exact amount of stopping down will depend on lens quality. On my 35L I stop down from 1.4 to 1.8 or maybe 2.0. On my 16-35L I stop down from 2.8 to 3.5 or maybe 4.0.

ISO: This one really depends on your camera. You want it high enough to catch faint light, but not so high to be very noisy. Since you're typically using a long exposure for meteors, I find that I can usually get away with a medium/low ISO (400-640) and still capture decent light.

Shutter speed: if you don't want star trailing, use 1,000/(focal length) to determine your max exposure time. Remember to include any crop factor in your focal length. So if you're shooting 15mm on a crop body, max exposure time = 1,000/(15x1.6) = 41 seconds. You can then always stack the individual frames to create star trails.

Watch your histogram -- if your histogram is peaking far to the right you have a lot of background light pollution and want to either stop down the aperture or lower the ISO or shorten the exposure. This obviously does not apply if you have a bright light source in your frame, which will make your histogram peak to the right (e.g. the lit-up building at the bottom of your sample pic).

Focusing is important -- just setting the lens at infinity may not work. Use LiveView at 10x + trial-and-error to get it right. Focus also shifts with temperature. So if you set focus at say 9pm and then start shooting at 1am, re-check focus right before shooting.

[DeutschBag]

Wow - thanks Fuzz! Great info. Way better than anything I found online searching. I guess I forgot to mention what I was shooting with (duh): 5dmii, and a choice of lenses, all L series. Above was taken with my super wide. Probably won't be using that and will use the 24-105 tonight instead.

I like the idea of star trails with a meteor or two streaking straight across. I'll work on that tonight - if these clouds go away. It's supposed to be clear today/tonight, but the forecast has been off all week. Maybe the clouds will go away after sunset. Luckily, they turn the lights off on the church across the road (the really bright building) at 11pm. Should be quite a bit darker tonight when I have the camera out.

thanks again!

[DeutschBag]

Skunked due to sleeping through the best hours and then fog in the very early morning. I did take a couple of shots just to test out some settings and did get much better results. Setting the focus to just under infinity worked really well on the 24-105, along with the f4.0 on this slow lens and using an iso between 400-800 (I played around and didn't notice a big difference in this range). I haven't processed anything yet, but may do so later and post. Thanks again for the tips, Fuzz.

[Chainsaw_Willie]

Focusing has always been the hardest thing for me - it's a pain, no way around it. Each lens is a little different and as mentioned you can't just crank it over to infinity.

I use fuzz's method - turn on live-view, crank the ISO up to maximum, use the digital zoom and zoom into maximum then start hunting for a bright star in the screen. Once I find it I can set the focus to it's sharpest point then reset the ISO & etc. Make sure the lens is set to the focal length you're going to use as well, most lenses will lose focus as the focal length changes.

I didn't realize the perseids were last night or I could've gotten some good shots. I was at my cousin's place out on the Peninsula where there is very little light pollution but I didn't have my tripod with me.

[Tippster]

Looks like you need to stabilize your tripod a little as well, Deutsch. At the very least hang your camera bag on it.