Watch photography 101-2: Aperture

[Gedanken]

Okay, so some of the guys here have gotten the hang of the idea that apart from setting up or finding the right lighting, you can adjust your shutter speed and aperture to get the right amount of light on your lens. Then you discover that if your shutter speed's too slow, your pictures come out blurry so increasing your aperture's a better solution. If that's the case, why bother with shutter speed at all?

Apart from the amount of light passing through the lens, the other thing that changes when you change aperture is your depth of field. Depth of field is the part of the image that appears sharp. The shallower your depth of field, the fewer things that are in focus. You can increase your depth of field by decreasing your aperture. Note that the F-stop figure, e.g. f/4, f/11, is inversely related to the aperture size - the larger the number, the smaller the aperture.

Here's a demonstration. I've got my SD, DJ and Tudor at different distances from the camera, and I've focussed on the 25 mark on the SD's bezel. here's a shot with the aperture size maxed out at F1.8:



As you can see, there's not a whole lot in focus. Even the SD's dial, which is just a touch further away from the lens than the bezel, isn't in sharp focus. Let's try decreasing the aperture by going to F7.1 - the focus is still on the SD's bezel:



Now the SD's dial is in focus, and the DJ's coming into focus as well, but the Tudor which is furthest back is still blurry. Cranking it up to F22 produces this:



Now all three watches are in focus 9although the Tudor's still a bit off). The larger your aperture, the more things in the picture that are in focus because the depth of field takes in objects ata greater range of distance.

Note, however, that as I increased the F-number, I also decreased the shutter speed so that all thee photos are equally bright.

Have fun playing with aperture size and shutter speed to find which combinations produce the best shot!

[OYSTERMANN]

Great post and very informative about the dark art of shutter speeds and depth of field to get the best shots.

[oneillba]

great photos to accompany the tutorial. informative.

[Ashley]

I love the last shot, that TT DJ has a beautiful sparkle!

[warrenmich]

I cant find those settings on my camera....
I spent good money on this thing!



I actually leave the photos to my Wife. This is a good way to get HER hooked on TRF!!!!

Thanks!

[unclesallie]

i cannot get close enough to the subject. what is the proper lens...(i have a 4 year old Canon Rebel XT, Digital SLR)? any help appreciated.
thanks,
dan

[TheDude]

Well, when you talk about macro photography sometimes it's not enough to dial in even the smallest aperture to get everything into focus that you might want.

An advanced technique (focus stacking) allows you to mask different focus areas from multiple exposures to produce a single image with all the areas in focus that you might want...


http://en.wikipedia.org/wiki/Focus_stacking



Also, remember that setting the aperture to very small openings hurts lens performance. This is a good read.

http://www.cambridgeincolour.com/tut...hotography.htm

[TheDude]

Originally Posted by unclesallie

i cannot get close enough to the subject. what is the proper lens...(i have a 4 year old Canon Rebel XT, Digital SLR)? any help appreciated.
thanks,
dan

You need either a purpose-made macro/micro lens, or something to alter the properties of an existing lens you might have. Some of the options include extension tubes and close-up filters.

[Gedanken]

Originally Posted by TheDude

Also, remember that setting the aperture to very small openings hurts lens performance. This is a good read.

http://www.cambridgeincolour.com/tut...hotography.htm

So THAT's what it is! Thanks for the link, Patrick - my photos alwasy seemed to come put best between f/8 f/14, but I never knew about diffraction limits.

I like extension tubes - I got a set of Kenkos and they're great value for money.