Questions from a noob

bsquared

Hello all,
I am a noob to this forum and to photography as well, and was hoping some folks here could give me a hand with a couple of questions that I have, and maybe some advice to help me avoid some pitfalls you may have encountered.
About me, I am 32 year old returning Electrical Engineering student with about a year left to go at Arizona State and have been a member at ADVrider since 2005. I ride my motorcycle nearly every day and end up doing a lot of exploring that way. I enjoy taking pictures of the people and places I see on my travels and I would like to get into some of the more artsy-fartsy aspects of photography.
After having a couple of p/s cameras I bought a Minota Dimage 7hi in 2004, which allowed a little bit more creativity in how I took photos and overall I was very happy with it…… but mine was one of those that had a bad sony ccd which of course did not crop up until after sony bought minolta and after waiting 4 months for them to replace the ccd, I received a letter saying they would only offer me a $300 credit towards a new camera. They had nothing like the 7hi so angrily I accepted a dsc-T9. The sony is a good p/s camera but lately I have found myself wanting something with more control. So I have been thinking about getting a DSLR.


Information I have garnered thus far:

1. Glass is much more important than the body
2. Skill is much more important than the glass or the body
3. It seems to me that the prices of consumer dslrs have pretty much negated price as a reason to get a prosumer camera like the 7hi instead of a dslr
4. I will likely end up spending much more on glass than the body so choose a body that fits the glass I want
5. I know I want something with the capability of using AA’s due to the fact I may be away from wall outlets on trips

Questions I have:

1. What do all of the numbers mean? I have taken a basic optics class (physics), so I understand the thin-lens relationships between object, image (size, real/ imaginary), focal length, radius of curvature and understand the concepts of chromatic aberration, resolvability etc… However I am not clear as to what the numbers printed on the lens represent. I do know (I think) that the f-number range (focal length/aperture) represents the range of different exposure times you can use while keeping the light intensity on the ccd constant, and that a longer focal length gives a larger image to the ccd at a fixed object distance, and that you always get a real, inverted image on the ccd. Beyond that I’m lost.
2. What would be the best lens or pair of lenses to start with If I want to take pictures of vistas, people, stills, action. Is there “a” lens that can do all of these “o.k.”?
3. If I was generally happy with the 7hi but would like to have some of the benefits of a dslr, can you make a recommendation? Does the possibly wider availability (cheaper) of canon glass due to canon's popularity make it the best choice financially in the long run?
   

I am not the typical starving student but I do need to keep the initial purchase price of body and first lens sub $800. What would you buy on
that budget?
There is an Oly E-500 with Sigma 55-200 mm 1:4-5.6 and 14-45mm 1:3.5-5.6 Olympus Zuiko on C.L locally which I think I might be able to get sub $400 is this a good starter kit?

Cool Forum, you guys take some pretty neat pictures!

mwgrice

Here's a review (on dgrin, no less) of a good book on exposure, Bryan Peterson's "Understanding Exposure."

http://dgrin.smugmug.com/gallery/1085479

To give you a real quick summary, the F-stop determines both how much of the image will be in focus and how much light is let in. A small F-stop number lets in a lot of light, but only a small part of the area in front of the camera will be in focus. A large F-stop number lets in much less light, but puts a large part of the area in front of the camera into focus.

Let's say you're taking a picture of some people in front of a mountain. With a small F-stop (like 2.0), if you focus on the people the mountain will and the background will not be in focus. With a larger F-stop (like F16), you can get both the people and the background into focus. Peterson's book had a nice description of this, as well as why you might want to choose one or the other from an artistic perspective.

Focal length is easier to figure out. Go to a camera store and try out a camera with a zoom lens with a wide range, and you'll get it easily enough. The two lenses you're looking at would give you a pretty nice range of focal lengths. If I had to pick one of the two and not knowing anything else, I would pick the 14-45mm lens. That's going to be better for landscapes, and you can always stand closer to the people.

bsquared

mwgrice wrote:

Here's a review (on dgrin, no less) of a good book on exposure, Bryan Peterson's "Understanding Exposure."

http://dgrin.smugmug.com/gallery/1085479

To give you a real quick summary, the F-stop determines both how much of the image will be in focus and how much light is let in. A small F-stop number lets in a lot of light, but only a small part of the area in front of the camera will be in focus. A large F-stop number lets in much less light, but puts a large part of the area in front of the camera into focus.

Let's say you're taking a picture of some people in front of a mountain. With a small F-stop (like 2.0), if you focus on the people the mountain will and the background will not be in focus. With a larger F-stop (like F16), you can get both the people and the background into focus. Peterson's book had a nice description of this, as well as why you might want to choose one or the other from an artistic perspective.

Focal length is easier to figure out. Go to a camera store and try out a camera with a zoom lens with a wide range, and you'll get it easily enough. The two lenses you're looking at would give you a pretty nice range of focal lengths. If I had to pick one of the two and not knowing anything else, I would pick the 14-45mm lens. That's going to be better for landscapes, and you can always stand closer to the people.

Thanks

bsquared

I bought it yesterday and have read at least half of it already. Thanks again for the book tip, very informative!

If anyone has a link to a rigorous explanation of why the aperture affects DOF as it does, I would appreciate it. Although a correct physical understanding of the phenomena is not necessary, I know it will bug me until I figure it out.

Just pulled the trigger on an Oly Evolt E-510 + 2 lens kit yesterday, and will receive it later in the week! I can't wait to start taking horrible pictures with such a nice camera!

groovyone

I also picked up that book and found it helpful, especially when it came to shutter speed. For DOF I just shot a LOT when I got my DSLR. I'd pick something then keep shooting it at different aperatures to get a feel for how it impacted the shot. Now I rarely if ever leave Aperature priority mode, and if I do it is usually to flip to Manual.

hgernhardtjr

bsquared wrote:

If anyone has a link to a rigorous explanation of why the aperture affects DOF as it does, I would appreciate it.

Since you are in engineering and know math, about two-thirds of the way down, you will say "ah ha": http://www.vanwalree.com/optics/dofderivation.html

bsquared

hgernhardtjr wrote:

Since you are in engineering and know math, about two-thirds of the way down, you will say "ah ha": http://www.vanwalree.com/optics/dofderivation.html

Thanks for the link, I have enough of a grasp to quit letting it bother me now. I kept thinking the DOF phenomena had something to do with matter-waves. Turns out that a system of ray diagrams explains it.

pathfinder

As the fstops get higher - f16, f18, f22 - the aperture gets smaller and smaller until it becomes effectively a pinhole, and a pinhole camera ( or a camera obscura ) is in focus at all subject distances - because a pinhole omits all light rays that are bent by a lens.

All light rays that pass through the optical center of a lens are not refracted or bent. A pin hole, or a very small aperture, only allows light rays that do not need refraction to be in focus.