I'm easing in to using my new camera, the Canon T5i, so I did a couple test shots on familiar objects using a technique I already know: Stacking short exposure images from a DSLR on a fixed tripod. I wasn't going for a new personal best or anything, but I wanted to take some short stacks to see how the new camera compares to the Rebel XT.
The first thing I noticed was that my memory card fills up A LOT faster with 18 megapixel RAW files. I only got about 150 shots where with the 8 megapixel XT I was getting closer to 250 in a single memory card. I actually filled the memory card, dumped the files, and went back out to shoot more a total of 3 times to take advantage of what seemed to be the one clear night in December.
 |
| Andromeda (M31) stack of 24 subs, 36 darks, 12 bias at 300mm, f/5.6, ISO 3200, 1.3 sec |
 |
| Orion Nebula (M42) crop from stack of 42 subs, 36 darks, 12 bias at 300mm, f/5.6, ISO 3200, 1.3 sec |
 |
| Orion Nebula 300mm crop, this time at ISO 6400, 11 subs, 23 darks, 21 bias, f/5.6, 1.3 sec |
 |
| Pleiades (M45) stack of 34 subs, 23 darks, 21 bias, 300mm, f/5.6, ISO 6400, 1.3 sec |
Although I only did short stacks, I may have inadvertently achieved my best effort on the Orion Nebula with very minimal post-processing. Rather than working for an hour to bring out nebulosity, I had a fair amount of gray cloudiness emerge just from the fact that my ISO was higher. I think I like the ISO 3200 Orion better than the ISO 6400 due to the reduced noise. Either way, very promising for just a test shot of less than 50 light frames - and only 11 light frames for the ISO 6400 image!
Hi Eric,
ReplyDeleteGreat to see this technique works. I have tried a couple of times on Canon T2i with kit lens 55-250mm at 250mm, f/5.6, 1.3s exposure, ISO 6400, but have not had any success.
Not sure if i am doing anything wrong. Any tips/suggestions?
I have read somewhere that we should be using wide angle and not telephoto, and have tried my 18-55 kit lens as well with exactly the same results.
Thanks
Jake
Hi Jake, what software are you using to stack your frames? I use Deep Sky Stacker. I can't tell by your question if you are using a stacking method or trying to get a good exposure in a single shot. A single frame at 1.3 sec will almost be completely black - but after stacking hundreds of frames and cancelling out the noise with light, dark, bias, and flat frames you can tease out some detail. BugetAstro has a great stacking tutorial for fixed tripod, and this is an example of the best Orion Nebula I was able to do on a fixed tripod. A wide angle lens would let you take longer exposures without star trails but the trade off would be the amount of detail you see (e.g. it would be brighter but smaller).
ReplyDelete