Cherry Blossom

[zdog]

[/IMG]

Just started trying some macro. Having a really hard time with focus. This was aken on a tripod with a shutter realease and this was still the best I could do. Any other suggestions? Any other comments welcome too! Thanks!



Oops - thought I had posted the EXIF - it was there when I "previewed" - hopefully it will show up on second attempt....


Aperture f/11.0
Focal Length 100 mm
ISO Speed 200
Exposure Bias 0 EV
Flash Off, Did not fire

[windrider86]

If you could post your exif info for us we may be able to tell why your having trouble with focus

[chicagojohn]

Originally Posted by zdog

;1202382Just started trying some macro. Having a really hard time with focus. This was aken on a tripod with a shutter realease and this was still the best I could do. Any other suggestions? Any other comments welcome too! Thanks!

Aperture f/11.0
Focal Length 100 mm
ISO Speed 200
Exposure Bias 0 EV
Flash Off, Did not fire

Hi zdog,

I'm trying to learn how to do macro too, and depth of field is difficult. You said you were using a tripod, and this flower wasn't moving, but the subject isn't a flat, two-dimensional one; it has depth.

So, I would recommend that you go as high as possible in f/number: The smaller the aperture, the greater the depth of field.

How high can you go with your lens? f/22 or maybe f/32?

Lets say you go from f/10 to f/32. The actual diameter of the aperture is equal to the focal length divided by the f/number. So at f/10 you have a diameter of 10 mm (100mm / 10), a little less than half an inch if you, like me, think in the English system. At f/32, the diameter is going to be only about 3 mm or less than 1/8 inch (100mm/32). That would make a big difference in depth of field.

But you will have to compensate the exposure value, EV. Because the light falling on the sensor varies with the area of the aperture, not its diameter, and because the area varies with the square of the diameter (diameter X diameter), going from f/10 to f/32, squaring the f/number would compare areas of 10 X 10 = 100 with 32 X 32 = 1024 or about 10 times less light at f/32 versus f/10.

Every time you double the light, that is 1 EV or 1 stop. So going from f/10 to f/32 is between 3 and 4 stops (3.2 to be exact). So in order to compensate for this reduction in light, you would have to add 3 EV to either shutter speed or ISO or a combination of the two.

So with a tripod, and assuming no motion in the subject, the best alternative would probably to decrease shutter speed by three stops, and maybe 3.5 stops to sort of bracket exposure.

Unfortunately, you don't say what your shutter speed was, and not knowing the incident light metering, I can only guess. So let's say the light was bright, like full sunlight, and you may have been at 1/30 s. Three EV, 3 stops, would mean going from 1/30 to 1/4 s; 1/30 to 1/15 is 1 stop, 1/15 to 1/8 is 2. amd 1/8 to 1/4 is three. So if you wanted to try 1/4 (assuming you were indeed at 1/30 initially), then you might also want to try going half a stop further. A full stop or EV would take you from 1/4 to 1/2, so intermediate would be like 3/8.

The other way you could go would be to increase ISO, and without a tripod and shutter release or with a subject that might move, this might have been a better option. Going 3 EV (stops) would have taken you from ISO 200 to ISO 1600; 200 to 400 is 1, 400 to 800 is 2, and 800 to 1600 is three. In digital this change is brought about by amplification. If the signal you are recording is low relative to noise, then when you amplify, you amplify both, and the signal-to-noise ratio may become unfavorable. In this case, I doubt that would happen, so you might be able to get away with it.

In some circumstances, the depth of the subject is just too great to capture the whole thing in focus even at small aperture. In such a case, if you have Photoshop Elements or another program that supports layers, you could take a series of images, with a tripod and cable or remote shutter release, with manual focus starting in front of the subject and working gradually to the back of the subject.

Then you would assemble and align these layers in PSE and use layer masks to make transparent the portions that are out of focus and opaque the portions that are in focus: A lot of work, maybe, but do you really have anything better to do with your spare time??

[chicagojohn]

Thank you, Windrider, for finally accepting my suggestion and dropping that annoying strobe! Now, if I could only get you to trade in your Harley for a Honda.... Seriously, I think it would be a better ride for an 86-year-old like you; especially if you would consider going to a trike.

[zdog]

Thank you for such a complete answer!!

I think its too late now for me to completely process it, will re-read multiple times when I get home from work tomorrow, Right now its off to bed after a long day of waterfalling. I'll also find out the shutter speed (and try to figure out why I missed copy and pasting it - ) and add to my post...

Thanks again - your response is very much appreciated!

[rengles]

was the flower moving? even tiny tiny movements could cause blur in a photo (i know chicagojohn assumed it's not moving - I just didn't see where you said that) I'm not sure how to deal with this best -- once you have your composition set up you could take several shots in a row, and hopefully will get one with little motion...

[RichardTaylor]

I'm not sure the subject was stationary either. Nothing looks sharp.

For tripod shots I use a focussing rail.
I use manual focus and then just rack the rail back & forth until it looks sharp in the viewfinder.


If you want to make sure it is not a subject movement problem try a couple of shots using a flash at maximum synch speed. The flash will freeze the subject and give you an idea if you have focussing problem or not.