Please help with 105 mm Macro!

[Cacia]

thanks Leesa! ....you explained that to me the other day. I have that. Now, with shutter speed (also a fraction) even though the number is going UP since it isn't expressed on the readout as a fraction, only the denominator, then, SS of 125 is smaller (faster) than 120, correct??

 

[Warren_L]

Please tell me at f22 the DOF is better. (first series)

Using it in macro or close up mode probably isn't the best demonstration in change of DOF as it is fairly narrow to begin with. But if you look at the detail on the "#" button on the phone, you can clearly see the difference. There is probably a greater difference between the shot using f/3.3 (wide open) and f/8, than if you were to compare f/11 and f/22.

also, 1/500th is the fastest SP , correct? The faster SP= less light, darker background "ambient light", or as Alcina described "richer, darker blue water color"

That depends on the camera and the mode that you're shooting in. As well, it may also depend on the sync speed of any lighting you might use. Using purely ambient light, shutter speeds on most cameras should get up to about 1/1000th, with some of the higher end cameras getting up to 1/8000 or faster. But really, these speeds are of limited use in underwater as over exposure due to too much light is typically not an issue.

The more blue you get is because of greater ambient light coming in from the background (i.e. the water) when you have a longer shutter speed or a bigger aperature. Incidentally, the hue of the background depends on the quality of water as well. In clear tropical waters, it appears more blue. In our local waters here, it appears more green.

I vote we take Warren as our personal advisor to Bali, Dennis.

I'm all for that.

 

[Cacia]

Okay Warren, the way I decided the DOF was better in the smaller aperature, higher f-stop was that the granite on your countertop came into focus.(last in the series #1) You did not say if I was right or wrong?

Yes or No...if my SS says 125 that is faster than 120, right? As I dial that up, my water gets bluer or ...greener (darker).

 

[Warren_L]

Yes, you are correct. The countertop is more in focus.

As for the shutter speed 125, on most cameras, if that is by itself, then it means 1/125. If shutter speed is in seconds, you would probably see something like 1" or 2" for 1 second or 2 seconds. There really isn't going to be much of a difference between 1/125 and 1/120.

 

[justleesa]

thanks Leesa! ....you explained that to me the other day. I have that. Now, with shutter speed (also a fraction) even though the number is going UP since it isn't expressed on the readout as a fraction, only the denominator, then, SS of 125 is smaller (faster) than 120, correct??

yup, just like the times at the olympics.

The bobsled guy with the time of 8 1/125' is faster than the guy with 8 1/120' (no idea what the actualy speeds might be). The smaller the fraction, the faster the time.

 

[pete340]

Please tell me at f22 the DOF is better. (first series)

Yes. But get in the habit of writing it as f/22, which is the "correct" notation. The 'f' there stands for focal length, and f/22 means that the size of the aperture (I don't remember offhand whether it's diameter or radius) is the focal length divided by 22. That also underscores how larger numbers mean smaller apertures.

 

[Diver Dennis]

Hey Warren. Is it just my computer or did your pictures disappear?

 

[Cacia]

thanks, Pete. I was really getting bogged down trying to make sense of the math and thinking bigger, smaller, faster, slower.

Yes, my camera expresses shutter speed by displaying the denominator only.

 

[Cacia]

I still see the phone demo....

 

[Warren_L]

Hey Warren. Is it just my computer or did your pictures disappear?

Should still be there unless my server went down. Try a refresh.