02-09-2015 11:52 PM
02-10-2015 09:49 AM - edited 02-10-2015 09:53 AM
There is no doubt the Canon EF-S 55-250mm f/4-5.6 IS STM Lens will take both of those kinds of picturers. The secondary question is, will it be the best at either or both? And that answer is, no.
If your budget is $300 bucks, this lens or any lens for that matter, is better than no lens. Truth is, this lens is a very nice lens and is a good buy. It just may be the best lens Canon makes in this category. Price and focal length.
But beware, on your camera it will perform like a 88-400mm would on a FF camera. This will make most "landscapes" a challenge unless they are on the Moon.
Go ahead and get it but start saving for another lens to compliment it. The great feature of a DSLR is interchangable lenses.
Keep the EF-S 17-55mm f/2.8 IS USM in mind. It is a little more expensive but is an outstanding lens. It is the best lens in this class. bar none. (not for the Moon)
02-11-2015 09:05 AM
OK, very easy. By far the best buy right now for a "super" telephoto is the Sigma 150-500mm f/5-6.3 APO DG OS HSM at $869.
Although not the Moon you can see this is a very good lens.
02-13-2015 12:23 PM
Are you trying for *just* the moon... or the moon with some landscape?
My astronomy software gives me a "field of view" marker that it places on the sky so that I can see how much area I'll get using a given telescope/eyepeice combination or telescope/camera combination (with or without focal-reducers or tele-extenders.) It's very handy when we want to image something and want to decide what equipment to place in the optical path to get the section of sky we want.
Anyway...the moon is about 1/2º from edge to edge (that's its "angular dimension").
A 600mm lens provides an angular field of view of about 2.1º wide (about 4 moon diameters wide) by about 1.4º tall (not quite 3 moon diameters... close, but not quite). If you wanted a nice close shot of the moon filling the frame, then somewhere around 1200mm... or even up to around 1400mm would work well. Of couse you could take it at a lower focal length and just crop in a bit to fill the frame. BUT... a camera lens up in those focal lengths would be crazy expensive and it'd be easier to do this with a telescope.
How did I know these angular dimensions for the lens focal length? I look them up: http://www.tawbaware.com/maxlyons/calc.htm
That site has lots of useful photographic calculators... one of which is the angular field of view calculator. As an avid amateur astronomer, I just happened to know that the moon is 1/2º wide, but that's also easily looked up on various internet sites.
When taking a photograph of the moon, know the "Loony 11" rule. That rule says that if you set the f-stop to f/11 then you can set your shutter speed to the inverse of the camera ISO setting and you'll nail the exposure. E.g. if your ISO is set to ISO 100, then set your shutter speed to 1/100th. If your ISO is at ISO 200, then set your shutter speed to 1/200th, etc. That perfect inverse relationship only works at f/11. (You can use other f-stops if you know how to trade a stop of aperture for a stop of shutter speed or ISO). If the moon is just barely rising, the thick atmosphere near the horizon will filter out a lot of light so you'd need to boost the exposure a bit, but once it's up in the sky and away from the horizon, use the Loony 11 rule.