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Ring Flash

Posted: Wed Feb 21, 2007 5:31 pm
by Gwenhwyfar
I want to get a Ring flash and was wondering if any one can recommend one for a 150mm sigma lens.

Posted: Wed Feb 21, 2007 9:19 pm
by Pete Eeles
What camera are you using? If it's a Canon, I have a Canon MR-14EX - but they don't come cheap! And with a Sigma lens you'll also need an adapter that screws onto the filter thread for the flash to attach itself (the "lip" this provides is already on all Canon lenses). Sigma now produce suitable ring flashes and they're probably just as good! But the MR-14EX is excellent at what it does.

I tend to use it for very close-up work, such as photographing butterfly eggs. For adult butterflies I found that the flash resulted in less-saturated colours and, as one would expect, the odd reflection. So last year I adjusted my "style" :) and changed my default settings to ISO 200, Shutter priority at 250ms, 1 stop under-exposed (and no flash). This resulted in the best images I have - in my humble opinion :)

Cheers,

- Pete

Ring Flash

Posted: Thu Feb 22, 2007 12:39 pm
by Chris Pickford
If you really want to use a ring flash - there are times when they are the best solution, but don't want to pay a lot, try using an old manual unit like the Centon one (£40) in manual mode. I've tried this route successfully for butterfly eggs and ants with a Nikon D70 and Tamron SP90 macro. Eg:-
Image

The ring reflections are a pain though......

Posted: Thu Feb 22, 2007 4:05 pm
by Wayne
Interesting infomation, I've been considering using flash this year. I can't afford a macro ring flash unit however....
I need a standard flash unit anyhoo so might experiment with that a bit.

I tried a very similar thing last year Pete, 1/200 to 2/300 shutter priority but I didn't stop the exposure down any. (I'll experiment with that)

Posted: Thu Feb 22, 2007 4:31 pm
by Pete Eeles
My logic was ...

1. To get more depth-of-field you need to close the aperture down.

2. If I close the aperture down, I need to let more light in.

3. To cater for that, I up the sensitivity (i.e. increase the ISO setting).

4. In addition I deliberately underexpose by a stop (sometimes two!). This has the benefit of allowing the aperture to stay (relatively) closed down (thereby increasing depth-of-field). Another advantage is that any "whites" don't get inadvertantly "burned out".

The disadvantage is that the out-of-the-camera image is sometimes pretty dark. But since I *always* shoot in RAW, then I can increase the exposure in the "digital darkroom" (i.e. software). On occasion you sometimes end up with very grainy pictures as a result - but most are OK.

As ever, experimentation is key to achieving the perfect balancing act!

Cheers,

- Pete

Posted: Thu Feb 22, 2007 4:39 pm
by Gwenhwyfar
Good to see some people coming out of hibernation! :)

Many thanks for the info, not sure which road i will eventually take, but does any one have - 'with a flash and without' pics just so I can see the difference.

Posted: Thu Feb 22, 2007 4:47 pm
by Pete Eeles
Scotch Argus:

With flash:

Image

Without flash:
Image

Marsh Fritillary:

With flash:
Image

Without flash:
Image

As I mentioned, I think you get better-saturated colours without flash. But take a look at Adrian Hoskins' website at:

http://www.learnaboutbutterflies.com/Bu ... graphy.htm

for an alternative perspective.

Cheers,

- Pete

Posted: Wed Feb 28, 2007 8:40 am
by JKT
I was wondering why you did not just increase the sensitivity, but the point about overexposure was a good one. Blue and red channnels are often a problem with the saturatated subjects we have.

I would not overdo it, though. The DSLR the results are better with higher ISO and correct exposure than with lower ISO and underexposure. Surprisingly, that is not always the case for P&S.

Posted: Wed Feb 28, 2007 10:10 am
by Pete Eeles
Good points.

The reason for underexposing (which I think I learned the hard way) was from reading various DSLR books/articles (Andy Rouse for example) where they suggest slightly underexposing so that highlights don't get burned out. The histogram is then to the left of centre. The various levels can then be "brought up" in the digital darkroom (software).

Cheers,

- Pete