Webcam or DSLR HD Video

[Steve91]

Hi guys,

Sorry if this has been asked many times before but I can't seem to find an answer. I know that webcams are widely used as a cheap alternative for planetary photography but is there any reason why I can't use my DSLR to do the same job? I mean it has a HD video recording mode and it attaches to my scope properly and is stable, I've never heard anyone mention it before and just wondered if it was possible and if not how come?

Thanks

Steve 

[michael.h.f.wilkinson]

You can use it, but the higher-end better webcams tend to get better results. I am pretty sure the HD-video mode is compressed, which is something you do not want. Webcams can transmit uncompressed video, avoiding MPEG artefacts which degrade the result

[oldpink]

I use both (well my ASI is basically a webcam)

what I have found is I get far more detail from the webcam than from the DSLR

if you plan to use the DSLR you really need live view mode and software likd APT or Back Yard EOS to get the best results

[Steve91]

Thanks for the replies guys,

So are we saying that I could use my DSLR but I would still get better results with a £5 xbox livecam? I've read the guide on modding them and it seems easy enough. I never thought about the compressed video formats of a DSLR, I haven't checked out what it records in but like you said it's probably going to be MP4 or something similar.

It terms of webcams is there a significant difference between say an xbox livecam and a Philips Toucam?

Thanks 

[Steve91]

Another quick question, I have a Nikon D3100, what software would be suitable for this camera as everything I've seen so far is geared towards Canon. I understand Canon are better for astro but for now I only have my Nikon. Backyard EOS seems like a great piece of software but I cant use it with my Nikon, is there an alternative? 

[mitchelln]

Thanks for the replies guys,

So are we saying that I could use my DSLR but I would still get better results with a £5 xbox livecam? I've read the guide on modding them and it seems easy enough. I never thought about the compressed video formats of a DSLR, I haven't checked out what it records in but like you said it's probably going to be MP4 or something similar.

It terms of webcams is there a significant difference between say an xbox livecam and a Philips Toucam?

Thanks 

I'm going to stick my neck out here and say these days the you won't get better results with a £5 webcam (that will need modding anyway) than a late generation DSLR. Those days are over. With a DSLR you will get more pixels onto the target with a high quality and sensitive sensor. Latest gen DSLR's compression algorithms are not going to lose detail on a pretty static planet especially if you shoot thousands of frames.

I have a Canon 7D, which I control from my Android phone so I don't wobble the mount. So I can image planets without lugging around a laptop and associated paraphernalia. I just slot in the camera, setup ISO, shutter etc on the phone (a Galaxy Note 2 with a nice big screen), focus using the zoomed liveview (also on the phone) and click record.

I tried a fully modded Philips SPC900 (which is supposed to be the webcam to have) and got very frustrated with it. I probably just haven't got the patience, but I couldn't achieve anything like the results I get with my Canon. I'm in this hobby to enjoy it, so spending hours swearing at cables coming out, stubbornly black screens where a planet should be and Windows 7 is not something I want to do

I'm also not a serious AP who does serious DSO work that requires guiding and super sensitive cams, but then you're not going to be able to do that with a cheap webcam either.

Of course this is my personal take on all this. There are very strong opinions on all this as I'm sure we'll see shortly! But my advice is, if you already have a DSLR then give it a go. What have you got to lose?

[Leveye]

I'm getting great results using my Canon at 30fps. I'm also not using any software just the camera using live view and a remote timer to so using either a Nikon or Canon should not matter. I do use a tracking mount autoguiding with PHD2 though.

[Steve91]

Very true Mitchelin, i have my DSLR so why not try it? I'm not against a webcam at all and im not against messing around with it to make it work better but my logic (being right or wrong) was that surely a £400 DSLR is going to perform better than a £5 webcam? 

I will test it and see what I get, and either way a fiver isn't going to bankrupt me  

Just need to find some nikon friendly software for the photography side of things too

[michael.h.f.wilkinson]

Having many more pixels on target does not help if your webcam already samples the image at the Nyquist rate or just. In fact it will degrade the image. If you use more pixels than the resolution of the optics allows, you are "diluting" the signal, leading to worse signal to noise. A £5 webcam might produce worse results than a £400 DSLR, I agree, and I have seen some respectable results on SGL. However, an SPC900NC (which had a decent CCD chip) can yield results that better the ones I have seen from DSLRs.

If you have a DSLR and don't have a webcam, just go for it and see if you like it. Once you are hooked, you can always invest in a planetary camera (and skip the £5 webcam).

[Russe]

A DSLR would certainly be easier to focus. I remember those cold frosty nights on a rickety Alt/Az mount that wobbled loads when I tried to move the focusser on the Mak... aaargh... it taught me a lot about patience.

[oldpink]

two images first taken by the ASI 120MC and the second with the Canon 600D (BYEOS x5 mode) both had a 2x Barlow on

[Russe]

An interesting comparison!!

Both done 28/2/14 between 19:50 and 20:10?

[oldpink]

An interesting comparison!!

Both done 28/2/14 between 19:50 and 20:10?

yes I was doing a side by side comparison so that viewing and temps were constant

TBH I think the ASI just has the edge with its faster FPS of around 100 where the Canon was running about 30

[Russe]

I agree.

[mitchelln]

Great pictures oldpink. It seems the 600D is proving to be a very capable astro imager. You can pick up an astro modded one for £369 now.

Here's a couple of comparisons I did with my Canon 7D and SPC900 (right):

and (probably unfairly!) M57:

Shots were taken within minutes on nights with excellent seeing all night. My SPC900 has the LX mod by the way.

Like I say, I didn't spend more than a few hours fiddling with the SPC900 capture settings and there are no doubt people who can post much much better SPC900 images. With two small children it's all a question of time with me and I'm happy with my "5 minute setup and go" Canon shots.