foxfirerodandgun Loc: Stony Creek, VA

I'm really not trying to confuse anyone, it's just that I have never delved into macro photography. I normally have just set the camera on auto and taken pictures as I go along and edit them later to suit my taste. The closest thing to macro that I have tried were some screw on rings when using a Minolta 7000. I apologize if I gave you the wrong impression. Most of my digital picture taking has been using a tri pod indoors taking images of firearms and other items that I offered for sale online. In this setting I used the aperture mode and bracketed four to six different aperture settings in order to get the exposure that looked good to me. I would also take close up images of proof marks, blemishes, manufacture markings, etc. in order that any potential customer would have a much better idea of what the item looked like.

To be completely honest about it all, even though I've used DSLR cameras for 30+ years, I have never attempted to learn the finer points of photography. Now that I am retired, and out of the firearm business, hence my question about f/stops and other subjects because I am the one who is somewhat confused and am not to old to learn new things.

Back in the 80's & 90's, before I converted to digital cameras, and when I had time to actually go out and look for subjects to photograph, I focused on mainly old, dilapidated, farm buildings. This was with film cameras and my point, shoot, and hope for the best attitude. I would get lucky sometimes and end up with a image that looked pretty good to me. Until now, I just plain did not have the "want to" learn any of the technical stuff attitude. Now I find that I want to challenge myself to learn more. Again, I apologize if I gave you the wrong impression.

josephl1331

Nice explanation. Now to get out the camera and take the same picture at different settings.

foxfirerodandgun Loc: Stony Creek, VA

I will be doing this on Saturday. We have Bible School and there will be a mess of "Little Munchkins" running around. Our BS only lasts one day. We are rural and the children have lots of outdoor activities to do. It's normally is a hoot. I really like being around kids. My wife's grandchildren will be there too.

lamiaceae Loc: San Luis Obispo County, CA

And more expensive usually better zoom lens have one wide-open stop, say f/2.8, and the lens may have a complete range of stops of f/2.8 to f/22 through out its zoom focal lengths. For example I have both a "kit" f/3.5-5.6 18-55mm Zoom Lens and a higher end f/2.8 16-50mm Zoom Lens. There is a vast difference in price between to two, both same brand.

lamiaceae Loc: San Luis Obispo County, CA

Nnooooooooooo, of course. With a (film) box camera, perhaps. LOL

lamiaceae Loc: San Luis Obispo County, CA

Yup, good reason to write stops as f/1.4 to say f/22. And not F1.4 or 1:5.6.

ballsafire Loc: Lafayette, Louisiana

Please show me how "One half of 1 is 1.4, not as often thought, 2.0." I don't understand this math. Thanks!

BebuLamar

One half of 1 is 0.5 or half! An aperture of f/1.4 let half of the light thru the lens as compared to f/1.0.

ballsafire Loc: Lafayette, Louisiana

Thanks for quick answer! I guess f/1.4 is close enough but I was wondering - why not f/1.5 instead of 1.4. There has to be a reason why f/1.4 is used.

BebuLamar

Well it's actually 1.41421356237..... because it's the square root of 2.
Let me try to explain. For example a 50mm lens with f/1.0 would have the aperture diameter of 50mm because 50/50=1. Now the area of that opening (aperture) is (50/2)^2 x PI which is about 1963 squared mm. Half of that is 981.7 squared mm. The diameter of an opening of 981.7 squared mm would be 2x sqrt(981.7/PI)= 35.35mm. Now the f number would be 50/35.35=1.414.

I hope you get it. If not I will explain some more.

ballsafire Loc: Lafayette, Louisiana

Yes, yes! I can now understand how that stop number (1.4) got into the sequence -- the square root! I don't want to go any farther than your explanation -- even using PI. I'll bet you are among the few on this forum who could've given this answer!

RWR Loc: La Mesa, CA

f/1.5 is about 1/6 stop slower than f/1.4. I have a 5cm f/1.5 Ernst Leitz Wetzlar Summarit (Leica M), 50 f/1.5 Voightlander Nokton Aspherical (Leica M39), and a 75/1.5 Carl Zeiss Jena Biotar in Exakta mount.

foxfirerodandgun Loc: Stony Creek, VA

OK.... let me ask one LAST question regarding f/stops. Please just fill in the blank space at the end of each statement with either slower or faster. And I'm not trying to confuse anyone or ask a frivolous question. I just need to clearly understand a bit more.

Higher f number = smaller aperture = greater depth of field = blank shutter speed.
Lower f number = larger aperture = shallower depth of field = blank shutter speed.

Thanks.

BebuLamar

Let see if I understood you. You want us to fill in the blank shutter speed? If so

Higher f number = smaller aperture = greater depth of field = slower shutter speed= longer exposure time.
Lower f number = larger aperture = shallower depth of field = faster shutter speed= shorter exposure time.

User ID

Neither of you is mathematically correct.
Look it up.