DSLR Camera lens selection

I know there are some knowledgeable camera folks here. as mentioned in my gibberish thread, i bought a used DSLR camera for use with my telescope, because this style camera could be mounted directly onto the telescope. having never used a DSLR, it was suggested to me that i pickup a lens, and just take pictures to help me learn what the functions do.
My camera takes Canon EF, and EF-S mount lenses (it is a Canon EOS Rebel T2i 550D, body only). i have googled tutorials until my eyes blurred, and read the manual until the same. what i need is an opinion, rather than flat facts. if i want to learn the various features of my camera, with only one lens (to start), what should i look for?

I have my eye on a: 50-200mm F/3.5-4.5
it is well used, but still works. it is stated to have working auto-focus (with manual, of course). it probably needs a good cleaning. (some lens fungus?)
what would this lens be good for?

Thanks in advance for any help. :smiley:


That is a nice general purpose lens. You would get a lot of use out of it.

Lens fungus is usually inside the lens and cleaning the internals of a lens without messing it up is tricky. I'd be wary of buying a lens with fungus unless it's a super bargain where it's worth living with degraded image quality or having a go at cleaning.

yeah. a little wider angle and probably a bit more portable too. I use a polarizing filter with mine for outside shots. A tripod is a necessary addition too.

Can you get an adapter to use the camera with your telescope? I have a 12" reflector. Dobsonian though so it is not well suited for astrophotography.

I got an app for my phone called "Sky Map" for finding space objects. It was free and does a great job. Can't wait to see some of your photos.

For recreational photography with a large CCD camera I like using a fixed focal point lens and storing in the largest possible format. With such large images it is easy to crop the image later and still end up with a great picture. It makes it possible to capture natural light images when it is not possible with a zoom lens (minimum f-stop is too large). It eliminates having to fiddle with yet another thing. In my case a very low f-stop 50mm lens is my go-to lens.

For your Cannon 550, the ‘normal’ lens would be a 35 mm.so the 28-80 would cover a good range from (slightly) wide to a good portrait lens (a short telephoto.) i use a 35mm on my Nikon ‘crop sensor’ camera. It turns out that the sensor on most dslr cameras has better resolution and dynamic range than all but the most expensive astronomical ccd cameras. The sensor on your camera is a cmos sensor, similar to a ccd, but less expensive to produce.

You should be able to set a delay between pressing the button and the shot being taken but I still think a remote is better because there might still be some oscillations going on even after a delay. The remotes are super cheap but at least that will allow you to get good shots while you're waiting for one to be delivered.

I found the IR remote to not be terribly useful for my purposes since I'm not in front of the camera body in range of the IR receiver so I pretty much only use the wired remote. It uses a standard 2.5 mm phone connector so I was able to buy an extension cable to make it more convenient to use.

That does look like a nice remote. Wireless without the line of sight restriction imposed by the IR remote.

It's always fun to go the DIY route but when a reasonably priced commercial product is available with all the functionality you need sometimes it's worth just breaking out the credit card. Of course the Arduino-based trigger does offer other possibilities like time-lapse.

What about tying a string to the camera, up through a pulley, with a counterweight on the other end to nullify most of the camera weight?

Set up a tripod. A decent lighting stand would be a ready made, collapsible solution. Or just rig something up with whatever lumber/pipes/sticks/etc. you have handy.

What telescope do you have? I have resorted to gaffer's tape to stabilize my DSLR on the scope. (That should help with the pressed in mount too.) Here's a picture of Venus attempting a solar eclipse taken with my D700 attached (and taped!) to a 5 inch refractor: