Tiger Beetle Head Study

[beetleman]

Well, this is my first "HEAD STACK". I know it is not that great but I figured I would post it just for the Discussion aspect of it. The first thing I would say "Get a fresh subject" . This specimen is very dusty, take a look at Charles krebs` work and you will see what clean is . This is Cicindela Duodecimguttata--12-spotted tiger beetle. Lighting was from a full spectrum florescent bulb. I locked the mirror up and shot 18 pictures for the stack (Helicon Focus) at ISO 100, F/10, 3.2s in Av mode, slight crop, Canon 400D, Canon 100mm Macro with full set of Kenko tubes (68mm). Here is a full body shot I posted a while back. C&C is what I want.
http://www.photomacrography.net/forum/v ... cimguttata

[rjlittlefield]

Geez, I wish my first "head stack" had looked this good!

Yeah, OK, it's an old specimen. So what?

Technical comments... The lighting works pretty well here, might benefit from having a bigger source, but it's always hard to tell without trying. I did my early work with a 50-watt photoflood at close range (see Fig.6, here). Then I switched to ping-pong ball with halogen fiber, and now I find myself using a lot of Kleenex tissue (for diffusion, not tears). It occurs to me that single thickness of tissue between your light and the subject might be worth playing with. If you have something even more transmissive, that would be better. (Got any fiberglass mat lying around?)

The blue background looks good. There's some sensor dust (I think) above the antenna, right side of pic.

It's hard to tell about the resolution here. The posted image looks just a little bit fuzzy, but it's hard to say why. Play around the aperture to figure out what gives the best resolution you can afford. Then play around with sharpening in post-processing. For detail that's near the limits of the optics, you can often make visible what would otherwise be lost because of falloff in the lens MTF. I generally do most of my sharpening at full resolution, then resize for posting, and finally do one last sharpening at say 35%, 0.7 pixels just to compensate for JPEG compression, dirty eyeglasses, and who knows what else.

The stacking looks pretty clean. I'm not seeing any visibility errors in the bristles. As Charlie points out, those seem to go away with slightly smaller apertures like you're using here. There's one problem with a sharp transition to background, top of image just to the left of center. If you see those while you still have HF open, they're easy to touch up. Fixing it in Photoshop is problematic because once HF has been closed, all the registration info gets lost and there's no guarantee that the images will line up properly. In this case that area is so fuzzy that it would probably be fixable, but in general it saves time to check carefully for artifacts before closing HF. (I keep thinking that one of these days HF will get around to saving the registration info so that it could re-open an old file for touchup editing, but as far as I know that hasn't happened yet. Hhmm, come to think of it, I don't recall suggesting it to them. Maybe they just haven't thought of it yet.)

That's what catches my eye at the moment. Was there something specific that you wondered about?

--Rik

[beetleman]

Thank you Rik. This is exactly what I am looking for in comments on the picture. I can tell you one problem I was having and that was vibration. The macro rail and camera are on a tripod and the rail and the long lens look very unbalanced (bad center of gravity). I also had to tell the family to stop walking around while I took the shots because the floor was shaking Stability is something I have to work on.

[Ken Ramos]

Yeah...uh...um...whatever Rik said, I think. Nice first stacked head shot there Doug, the eyes look to have a bit of dust on 'em but thats okay.

[rjlittlefield]

I also had to tell the family to stop walking around while I took the shots because the floor was shaking Stability is something I have to work on.

Uh, yeah. Camera on tripod, subject on table is a bit short of optimal.

At this magnification, it would help a lot to get everything on the same tabletop. But even that is not as foolproof as you might think.

Just for grins, I just now clamped a dial indicator on my dining room table. That's a 3/4" top with a 3"x3/4" frame. Over a 16" span, the dial indicator jumped by 0.002" when my wife shut the oven door, 8 feet away. It jumped by 0.0005" when she just set a breadboard onto the countertop. I don't want to think about chopping onions, let alone footsteps. These numbers don't sound like much, but when your field is only 0.5" high, even the breadboard is 2 pixels.

--Rik

[Tony T]

If you had added another 18 images you would have got those front legs in focus as well as the humeral spots on the ant. part of the elytra.
I find these OOF areas very distracting. Also need some more lighting on the sides, too dark behind the left side of the labrum beneath the eyes and nasty shadow at base of left leg.

[beetleman]

Tony..I see your point about the lighting. I was using the light running along his right side and past the head. Definitely need another light source for his left side. Definitely good C&C for the beginner. Thank you

[Tony T]

., There's one problem with a sharp transition to background, top of image just to the left of center. If you see those while you still have HF open, they're easy to touch up. Fixing it in Photoshop is problematic because once HF has been closed, all the registration info gets lost and there's no guarantee that the images will line up properly. --Rik

How? is this a feature found in the Pro version? I have HF Lite.

[cactuspic]

Doug, great first head stack. The ist set of legs is either too blurry or not blurry enough given its prominence. The transitions and balences between focused and unfocused areas play out differently when focus stacking and takes a bit of getting used to.

While not criticism, I have two tips that may save you time that I learned the hard way. First , watch your metering. One of the effects highlights becoming focused is that they become brighter. The focused highlight in frame 47 may be 1 stop brighter than the diffuse out of focus highlights in the first frame. As Rik has indicated in the in the past, sometimes you have to deliberately underexpose to stop from blowing out your highlights. If you are seeking to maximize you exposure and have a constant light source, you can stop down, use your depth of field preview button, identify your hot spots, and check specific exposures requirements for the slices with the hottest of the hot.

Second, check your battery and camera memory before doing an extensive stack. As you are finding out, movement is the bugaboo of stacking. Jostling the camera by inserting a battery or a card mid-stack can destroy registration. You think your tripod is locked down and won't move but it does not take much. While I have successfully changes cards and batteries....

Hope to see more.

Irwin

[rjlittlefield]

If you see those while you still have HF open, they're easy to touch up.

How? is this a feature found in the Pro version? I have HF Lite.

Yes, it's in the Pro version. Check out their web page, first bullet:
* retouching brush to clone from aligned source images to the resulting image (cannot be performed with external photo editor, Windows v.4.0+).

--Rik

[cactuspic]

Rik I have a workaround that will allow you to pull a saved image back into Helicon to so you can re-edit using the retouching brush. Since the response is technical in nature, a little long and tangental to the main image, I have put the information in a new post: this posting

[Cyclops]

Wow cracking, and menacing, shot!

[JoanYoung]

Gosh Doug..that one is as ugly as any we have here!! Great pic though!!