Canon Lenses Aperture
What are the best settings and lenses for astro-photography using only the camera and the telescope?

I have a Canon Digital Rebel XTi with 18-55mm standard lens has an aperture of 3.5-5.6 I think and I wondered what is the best scenario for the combination of the camera and lens best results for photographing the night sky (in terms of shutter speed, aperture, white balance, etc.) I have a tripod, but is not equipped to receive the planets – without equatorial mount if that is what is called. Also, I like to get a low cost but still nice extra lens that may be more suitable for astro-photography without a telescope, any suggestions?

something to try, go into your menu and activate the exposure time limiter noise, then get a remote control and a good, strudy, heavy tri pod, go to a place with a good view of the night sky, make sure its a clear night and no wind, set the cam console with the remote plugged in, the use of an F 16 – Opening 20 and the point of the cam in the most important grouping of star … Now, the zoom lens as you go and put your camera in manual mode, set the shutter to "bulb" mode, that do this: when you press the remote control, the shutter opens, let it stay open as long as you want .. more usual 30 minutes to an hour, then click the remote again and closes the shutter, Now, let the camera to write the image to the card, this will take about the same time as it did to make the shot. What youll get: Star trails … youll be able to see the trails of light in a circular pattern made by the stars moving across the sky, while his camera was filming it .. but must be absolutely, in a place where there will be no ambient light at all and a place without wind or vibrations from you walking around and such.

Canon Lenses Aperture

Why the Canon 17-55mm about $ 900 while 18-55mm is about $ 150?

I know that the base material of the lens the camera: the aperture, ISO, depth of field, shutter speed and so on. I also know a bit of focal length, but I do not understand why What is the Canon 17-55mm much more expensive than the 18-55mm? You can explain that compared to all the jargon of the camera and I hope you understand.

There is glass quality, build quality and image quality. The 18-55 has a variable maximum aperture. This means that in 18 mm can be used also larger than f/3.5, but with the increasing opening up to f/5.6 zoom which is the most open, you can use 55 mm. This objective is also likely pretty cheap plastic construction and probably even has a plastic backing. The 17-55 is what is called a constant maximum aperture. You can use the 17 mm f/2.8 55 mm. USM is also a way that the autofocus is very fast and silent. The quality of construction will be much equally well, and a frame Metal. With goals to get what you pay for. $ 900 sounds quite reasonable for the lens. When she was a target of the L series which cost twice what he does. Edit-I agree that if you want a similar quality for less money than the Tamron 17-50 is a better solution for you. I know that many people using lenses on their cameras and about 90% of the time.

Lens/Aperture Relationship