Macro work
 

I've been really enjoying using my Sigma 105 macro but I find myself struggling with the narrow DOF I get as I get closer and closer to the 1:1 end of the focus range , I know if I close the aperture down I can increase the DOF but at this end of the range the difference between f/4 and f/16 is only 1.5mm to 5.8mm .

If any one has any advice or tips on the type of settings that they find work for them I would be very grateful to hear them .

These are some of my latest images all taken hand held and the lens is the pre OS version , all critique welcome .


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[URL="http://media.digitalcameraworld.com/forum/gallery/files/1/4/1/1/6/5/22.jpg"][IMG]http://media.digitalcameraworld.com/forum/gallery/files/1/4/1/1/6/5/22.jpg[/IMG][/URL]


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I know this last one has that dam twig in the background and it would be better if it's wings were apart and it was a side shot but it's the best inflight Dragonfly shot I've taken so I had to put it in :) .

Thanks for looking

Mark

The detail in these photos is really good Mark, particularly the stationary dragon fly.Focus is spot on.
And I love the colour in the legs on the spider and the backlighting.
And you've done really well hand holding. Good work.

With regards to DOF, I'm not the best person to offer advice on this as its something I have a problem with too. Sorry.

Great shots Mark I think we all suffer from that problem and photo stacking seems to be the only way, but rather impossible hand holding, I need a tripod for shots like yours.

Great shots, the fall off is an issue when you are so close the only solutions I know of are to either pull back a bit and crop heavilly to get the close up detail or as already mentioned use focus stacking.

To do focus stacking accurately you really need a good solid tripod and depending on how many images you are going to stack probably a focus rail as refocussing the lens can cause the image to enlarge or reduce where as with the rail you pull the whole camera back or forward with fine adjustments. Also stacking is a problem with a life specimen as the blighters have a tendancy to move.

I have read some people either shoot dead insects or pop them in the fridge for a while although my wife would have a fit with the latter;)

Here is a sample of a stacked macro I did using a Velbon focus rail:-

[url=http://www.flickr.com/photos/37871469@N03/7048264995/in/set-72157626873299895/lightbox/][img]http://farm8.staticflickr.com/7065/7048264995_dec77af708_b.jpg[/img][/url]

Thank you all very much for your kind words and suggestions on extending the DOF , I don't think focus stacking is for me as I do most of my work out in the field where even setting up a tripod can clear the surrounding area of wildlife in an instant . I'll have to try out a combination of shooting from further back and a narrower aperture or learn to get more creative with my composition and the curse of a shallow DOF .

Thanks once again

Mark

PS

Stunning detail on the lighter Dave .

Mark, as a very general rule of thumb, you'll get a 2mm DoF @ f2, 8mm @ f8, 16mm @ f16 and so on and so forth. You may find yourself taking more macro shots at f32 or above with backlighting or by increasing your ISO to 800 or 1600 to give yourself a fast enough shutterpeed to handhold it.

Try keeping the length of the insect parallel to the film plane is the best way, other than that use flash and a small aperture. The purists will say that lens diffraction will be a major problem, but I prefere my macro to have as much DOF as possible.

The attached image (quality reduced by DCW) as discussed in my thread "A question on image quality..." It does however show the DOF.

1/100 sec @ f/22 + macro flashgun.

Harry

[IMG]http://media.digitalcameraworld.com/forum/gallery/files/1/0/8/3/9/6/hover_flies.jpg[/IMG]

Cheers Ian , I know you said it's just a rule of thumb but the sigma has a min focus distance of 122mm to get the 1:1 ratio and at that distance the DOF is half your stated lengths ( according to my DOF calculator ) but using a higher ISO with smaller apertures to keep up the shutter speed is something I'm going to have to look into thanks .

Thanks a lot Harry you've just added a macro ring flash to my wish list , I know what you mean about the image quality on the site but with a max 900 pixel top edge we'll never see the real quality .

Mark