New Photography Webpage

[Greg Shutterbug]

I took a stab at putting a photography primer on my webpage. By writing it, it helped me to understand the basic concepts, so I wanted to share it with you.

I would really like any feedback on it - corrections, suggestions, or whatever. Thanks for looking and I hope it's helpful to some.

http://home1.gte.net/res0ak9f/camera.htm

Best Rgds, Greg

[nwpoland]

Hey,
You've got a lot of good info that is helpful to the newbie (specifically folks like me and my wife--she's very afraid of the complexities found on dSLRs even though you could just set it to full-auto or a program and be done with it).

I'm very interested in finding a site that would give practical scenarios to illustrate the relationships between aperature, shutter speed, etc. For example...what if you took let's say 3 different types of pictures: (1) portrait taken indoors, (2) action shot -- some kind of outdoor sports, (3) maybe a macro in poor lighting...I don't know. But then discussed how they would turn out based on the settings used. You could even give examples of the same composition taken with different settings so that the novice user would really see the difference instead of just reading about them in theory.

That would be the biggest help for me and I've yet to find it even after a lot of looking. Maybe someone else is doing it and I just have found it. IMHO, though, that would set you apart from the other sites that are giving similar information.

Thanks for sharing!

[John_Reed]

I took a stab at putting a photography primer on my webpage. By writing it, it helped me to understand the basic concepts, so I wanted to share it with you.

I would really like any feedback on it - corrections, suggestions, or whatever. Thanks for looking and I hope it's helpful to some.

http://home1.gte.net/res0ak9f/camera.htm

Best Rgds, GregVery thoughtful of you to put up that page. I had a quibble with at least one of your statements:
My Lumix DMC-FZ20 lens opening is f 2.8 through-out the complete focal length. So the aperture gets pretty large at long focal lengths (432mm/2.8=154mm), as the aperture must increase as the focal length increases to maintain the f-stop. The aperture on my camera gets so large that it cannot do super-fast shutter speeds when at it's lowest f-stop, due to the mechanical limitations of the shutter having to move so much (shutters often double as the aperture).
I think to be accurate you should be describing your FZ20's dimensions based on its true focal length, not its "35mm equivalent" focal length. The fact that it isn't the same as it would be for 35mm film is because the "crop factor" is so different because the CCD sensor is that much smaller than the 35mm's field of 24X36mm. So the physical aperture grows, at maximum FL, to 72mm/2.8=25.7mm, about an inch.

[Greg Shutterbug]

Very thoughtful of you to put up that page. I had a quibble with at least one of your statements:

I think to be accurate you should be describing your FZ20's dimensions based on its true focal length, not its "35mm equivalent" focal length. The fact that it isn't the same as it would be for 35mm film is because the "crop factor" is so different because the CCD sensor is that much smaller than the 35mm's field of 24X36mm. So the physical aperture grows, at maximum FL, to 72mm/2.8=25.7mm, about an inch.

John, thanks for the sugggestion. I have changed the page to reflect this. Before the change, it left the reader with the wrong idea about what the actual opening is. Now it's accurate per your input.

If anyone else has any inputs, I would like to hear them. Thank you. Greg
http://home1.gte.net/res0ak9f/camera.htm

[reyval2k]

**********************QUOTE***********************

My Lumix DMC-FZ20 lens opening is f 2.8 through-out the complete focal length. So the aperture gets pretty large at long focal lengths (432mm/2.8=154mm), as the aperture must increase as the focal length increases to maintain the f-stop. The aperture on my camera gets so large that it cannot do super-fast shutter speeds when at it's lowest f-stop, due to the mechanical limitations of the shutter having to move so much (shutters often double as the aperture).

**********************QUOTE***********************

This may be a dumb question, but do Point and Shoots have actual physical shutters like film cameras?

My understanding is shutters are a necesity with film cameras because of film's designed sensitivity to light.

But when it comes to sensors aren't they just charged on then off to capture an image? I believe a sensor is always exposed since if it weren't so, you wouldn't be able to see anything on the camera's LCD or EVF. When we press the shutter button what probably happens is the CCD simply "captures" whatever it had been already looking at. You know, like a screen capture from a DVD or something.

[reyval2k]

Continuing with that line of thought, this is probably why DSLRs don't have a preview function, meaning they have a physical shutter or mechanism that blocks the CCD until the shutter button is pressed; in which case it moves out of the way, revealing the image for capture. :confused:

Great primer Greg, in any case. Thanks for putting that stuff together. I too am a newbie and appreciate the effort and thank you for sharing. :)

[Greg Shutterbug]

My understanding is shutters are a necesity with film cameras because of film's designed sensitivity to light.

But when it comes to sensors aren't they just charged on then off to capture an image? I believe a sensor is always exposed since if it weren't so, you wouldn't be able to see anything on the camera's LCD or EVF. When we press the shutter button what probably happens is the CCD simply "captures" whatever it had been already looking at. You know, like a screen capture from a DVD or something.

Great question-- do (non-SLR) digital cameras have a shutter ?? Yes, you see the image when setting up the picture, so yes it's on at that time. But when you half-press the shutter release button, it freezes - I thought this was due to a shutter closing in front of the CCD.

[Shooter]

Excellent site... thanks!

Are you planning to update as you learn more? I use (but have no idea how it works) white balance, for example.

Perhaps a section on helping amateurs like me judge lenses? Usually the cheaper lenses offer a trade off but it is difficult for me to judge the pros and cons.

[Greg Shutterbug]

Thanks. These are good ideas. I just updated the site but still working on it.


http://home1.gte.net/res0ak9f/camera.htm

[Balrog]

Nice site, I like it .. a couple of things, though:
You say "the human eye has a focal length of approx 50mm, so the viewing angle is 43 degrees total (21.5 degrees each way)." ... there's a little bit of confusion over there: The actual focal length of a human eye is about 1.7 cm [Physics Factbook (http://hypertextbook.com/facts/2002/JuliaKhutoretskaya.shtml)] ... the 50mm figure you're referring to is the focal length of a 35mm camera lens that most closely approximates a human field of view (the 'normal' FOV lens). Even that figure is dependent on the format of the camera - I think for medium format cameras a 'normal' FOV lens is something like 150mm, while for your FZ20, for example, the equivalent focal length would be about 8mm.
Also, you might want to replace "CCD" with a more generic term like "sensor", to accomodate the fact that CMOS sensors are also becoming common among digital cameras..

[Greg Shutterbug]

Balrog, thanks for the feedback ! I made some changes based on your notes. Took out the stuff on the human eye for example. To date, I do not know of any higher quality cameras using CMOS imagers (we make them at the company I work for), except in some cell phones and cheap PC cameras. Any more info would be greatly appreciated. Thanks again ! Greg

[Balrog]

Higher quality cameras using CMOS? Canon DSLRs use CMOS sensors (RebelXT, 20D, etc.) ... and I think so does the Nikon D2x, now (it's a Sony CMOS sensor, iirc). CMOS has become popular in high-end DSLRs because it has less noise than CCD sensors.