Wednesday, 15 October 2014

Watching and writing

Today I watched Creative Wow: Drone Photography and Creative Wow: Macro Photography, both with Jack Davis on Creative Live. I wrote an article for my photo tips website as well.

Watching the workshops, I got the impression that Jack doesn't really know a lot about what he is talking about. That's not to say he doesn't know anything - he clearly does. Just he does not come off as an expert.

The Drone photography workshop was really just about how to operate a DJI Phantom II and then how to process the images (which is basically the same as any other photo). A lot of the info was new to me, but it seemed like he just had some experience with Drone Photography rather than being an expert. There was a guy in the audience (who was specially invited because of his experience) who obviously new a lot more than Jack.

He said that you can't create a panorama using a fisheye image, so it needs to be defished first. That may be true for Photoshop (I don't know), but certainly isn't true for other software.

In the Macro workshop he kept referring to dynamic range when he meant Depth of field. (If he did mean Dynamic Range, then what he was saying wouldn't make any sense). I think he does understand the difference between DR and DoF, just kept using the wrong term without realising it.

He stated that a reversing ring allows you to get much closer with any lens (or something along those lines), but actually any true macro lens above 50mm won't focus as close when it is reversed.

He said that using a really small aperture gives you image noise. But this is only true if you boost the ISO to compensate for the small aperture (or underexpose).

Now, this may be my misunderstanding, but he stated that the higher the bit depth, the greater the dynamic range. My understanding is that the bit depth deals with the gradation of tones (more tones = more even gradation) rather than the absolute exposure range that can be produced. I should probably read up on that a bit more to understand whether he is correct or not.

His macro shots he took using a high ISO, which resulted in grainy images. I guess that's a personal preference, but I think the images would have looked a lot better shot at a low ISO (and properly exposed).

When taking a shot with a zoom lens on extension tubes, he zoomed it in (to 200mm) and used the focusing ring for focusing. Maybe he mentioned it in a bit I missed, but I got the impression that he didn't realise that the shorter the focal length, the higher the magnification (with both a reversing ring and extension tubes).

I don't think he covered the use of close-up diopter filters or reversing a lens on another lens (both have the same effect) at all.

He didn't cover the use of flash at all (unless it was in a short bit I missed).

Most of the work he covered was close-up and not macro. I don't think he mentioned what macro means, though he did say that he would have preferred the course to be called Close-up and Macro photography, so maybe he did understand that.

He did cover focus stacking, but just in Photoshop and Helicon focus. He didn't cover any of the technical details of the best way to shoot a focus stack. And it's my understanding that Zerene stacker is the premier stacking software. Covering something like Zerene, CombineZP, and Photoshop CC probably would have made more sense than the PS CS6 - PS CC - Helicon Focus comparison he did.

He mentioned a few times that the Nikon D7100 has an FX size sensor, which gives a 1.5x multipler compared to a full frame DX sensor. (He got the terms FX and DX mixed up, F stands for Full Frame).

None of this detracts from his artistic ability. You don't necessarily have to understand how something works to achieve great photos. But I do think that understanding the technicalities behind how something works can help you achieve better results.

I also suspect that when you are presenting a show it is probably very easy to forget to mention things or use the wrong term to describe something. So it may well just have been the pressure of doing a live show making it look like he didn't know a lot.

One thing I had always thought was that adjustment layers in PS were non-destructive. In the sense that if you pull curves down in one adjustment layer and then pull the curves back up in another adjustment layer, then PS would calculate the processing based on all the adjustments together, in effect not performing any pixel munging. However, Jack stated that the adjustments in PS don't work the same way as they do in ACR, where it calculates the actual adjustments needed based on all the adjustments made to an image. I just tested this, and he appears to be correct. It looks like PS does process the image at each adjustment layer, moving up the layer stack.

So having a lot of adjustment layers can result in image degradation. It seems strange to me that PS should work like this.

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