I have read all the information and feel like I have an understanding of all that I need to do to get pictures of the milky way over the grand canyon.....but...I only have 2 options for camera Canon 7D with canon lens 17-55 2.8 or 50mm 1.4 I kind of feel a little bummed because I know I need a 35mm or less :( First out of the 2 which would be the best choice and then what can I do to compensate..just use a higher ISO? What would be a good shutter time be 30s? I am so excited but disappointed because I don't have the optimum lens. I also plan to try my hand with the sunrise and sunset. Just starting to dabble more with landscape, etc...what better place than the Grand Canyon..right? I will only be there for 2 days so I have to get it right..or at least close...or I will be greatly disappointed! I appreciate all your help! Teresa in Ohio
You can definitely shoot the Milky Way with a 17-55 mm f/2.8 lens on a crop sensor. I've shot it with a 20mm 2.8 on a 7D and it came out just fine! So long as you set the lens to 17mm you should be fine.
To shoot stars, you can follow the rule of 600. Just remember to multiply the focal length by 1.6 to get the appropriate time. In your case, that would be 17 * 1.6 = 27.2mm equivalent focal length. 600 / 27.2 = 22 seconds exposure.
You can compensate by increasing the ISO. I suggest you take several shots with different settings to see what works best. I'd start with the lens set to 17mm and try a 22 second exposure at ISO 800. If it's too dark, you can increase the ISO. If the movement of the stars is too great (too streaky), you can decrease the time the shutter is open and compensate with a higher ISO.
Another option you have is to borrow or rent a different camera and/or lens. A 2 day rental would not cost very much. For example, this website has a Canon 14mm f/2.8 lens for less than $100 for 7 days. (I've never used this service, it's just an example.) You might be able to find similar deals on other sites.
Since you are planning to take a landscape picture, it is advisable to use a lesser focal length lens to get a greater angle of view. In your case you should use 17mm to achieve this. And make sure you focus it manually, and focus it just before the infinity point in your focus ring. this could give u a better result in terms of focus.