Wasp Mimic Beetle

[Bios.]

Wasp Beetle (clytus arietis) by [[BIOSPHERE]], on Flickr


Wasp Beetle (clytus arietis) by [[BIOSPHERE]], on Flickr

See my flickr for the .exif info. For the second one I used a set of cheap extension tubes and they seemed to make my images a little bit soft. Does anyone know if using extension tubes can affect diffraction at smaller apertures?

Cheers.

 

[Davor]

Excellent capture! and very good results for f16 , did you use off camera flash built in flash?

 

[Bios.]

Thanks man. I used an off-camera 430ex with a DIY diffuser. I will put some pics of my set up on my flickr at some point.

 

[Davor]

yeah i would love to see this DIY difuser

 

[Overread]

At f16 (on the first shot) I'd be a little careful with the aperture since on crop sensor camera bodies (like the 500D) diffraction starts to really begin to take hold around this aperture, even at f13 you can see its effect fairly clearly if you do a series of test shots; though f13 is normally pretty safe (ie its not crippling and sharpening will restore almost all the details and crispness).

I personally shoot around f13 much of the time and only use f16 on odd occasions.

With your second shot your cheap tubes appear to be the very cheap kind that don't come with electrical contacts; which of course means your aperture can't be controlled from the lens. So I suspect (unless you used the aperture sticking trick) that your shot was taken wide open (ie aperture blades fully open). This might cause some softness to be apparent since most lenses are not their sharpest when used wide open (and the tubes are having a small effect on image quality by moving the lens from its prime position) which is why many people shoot a few stops down to get a boost to sharpness.

 

[Bios.]

Davor: I'll post a photo when I get round to it.

Overead: Yeah they are the cheapo kind and I know the stpping down trick. I usually use f11 with the extension tubes just so I can see through the viewfinder a bit better but I used f16 this time and I noticed a difference, though it could be missed focus. I've never done any rigorous testing but I've never really had much problem with using f16 without the tubes.

 

[Overread]

The thing is when you use tubes (as far as I am aware) the actual aperture of the resulting lens is reduced. So whilst you've set the aperture blades to f16, once you add in the tubes you've got an effective aperture that is smaller than f16. This isn't just lightloss, but also an actual aperture change so the depth of field is a little greater and the diffraction effect greater as well. As a result the softness you are seeing might be the result of this change.

However now that I double check your shutter speed and ISO are:
Shot 1 :1/80 ISO 200
Shot 2: 1/100, ISO 400

Now if you've got flash giving you lighting unless you're going to capture natural lighting in the shot as well (for which you need a perfectly still subject and camera - and no wind) you should really put the speed up at the fastest the camera lets you (1/200 or 1/250 at the common values). Also your ISO should be able to go lower, ISO 200 is ok, but 400 will start to show more noise and that might also be partly where you are losing some quality and detail in the second shot.
Again if you're going for more natural light dominance raising the ISO (thus lowering the flash amount needed) helps, at the cost of noise of course.

 

[Bios.]

I was trying to make sure the background wasn't black hence the shutter speed and ISO and I wanted it blurred so it was too far away too be lit properly by the flash.
I may do some tests at some point to get a clearer idea of how far I can push things but until then I'll just continue to learn by trial and error! Cheers for the info Overead.

 

[Bios.]

A re-edit to desaturate and lighten the background:


Wasp Beetle (clytus arietis) by [[BIOSPHERE]], on Flickr

And pics of the setup I used:
My diffuser is made with a cone of kitchen towel, taped into a plastic pot, lined with tinfoil, with a layer of copy paper on the tip of the cone to make a sort of beauty dish

My macro setup. by [[BIOSPHERE]], on Flickr

 

[ChrisA]

Nice shots. I like that first one. Very nicely done, good control of flash to get the background looking natural.

Could be slight subject movement in the second shot ? Possible slight diffraction if using a small aperture.

I often use ISO 400 on my 50D which is supposed to be noise prone. You can always remove this in PP.

 

[tyler_h]

Nice shots; and thanks for posting your setup too. Looks like a nice way to do it without the cost of the macro flashes; still need a real flash first before I can try it out though...

 

[Bios.]

Thanks Chris.

Tyler: Yeah cheaper and much more versatile than macro flashes however one day I hope to own the MP-E and MT-24ex combo! The only problems with this setup are that it's a little bulky and a bit fiddly to rearrange the flash, I need to get a ballhead or something similar to attach the flash to the bracket.