I was trying out my D800E, shooting a few bees on the rosemary bushes out back using my old AF 105D macro and a flash. The resolution of the camera is surprising, as expected. But I didn't expect the occasional rainbow colors on the wings of the bees.

I'll attach a center-section crop that shows what I'm talking about, reduced to 300KB. Hopefully still visible. My question is... moire, or just a natural prismatic effect? All thoughts welcome! Photo was taken at f/22, 1/250.

Thanks,
Ed

Attachment #1, (jpg file)

Hi Ed,

No. This is the natural iridescence caused by the parallel transparent surfaces of the insect's wings. Wikipedia puts it more clearly than I would. Think soap bubbles. The effect is the same.

I often see moire, and it is rarely an insuperable problem.

Colour aliasing I also see and sometimes it is so severe it that prevents use of a picture because its removal destroys too much detail. But I will not give up using my D800E because of that, it has too much going for it! The D2X and D3X were actually worse in this respect, but nobody seemed to notice........

Roderick

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At F22 refraction will likely blur the image enough to prevent moire, nice photo !

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A really nice photo, Ed.

Not to mention diffraction. The Nikon D800 Technical Guide cautions the onset of diffraction is around f/11, and your shot is at f/22. Where is the diffraction?

I did a series of photos with different lenses several months ago and could only notice softening at f/22

http://www.nikonians.org/forums/dcboard.php?az=set_threaded_mode&forum=430&topic_id=12618&prev_page=show_topic&gid=12618#14548

I don't see blur or softness in this image - am I missing something??? I'd like to learn how to identify it.

David

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Roderick,

Thanks! I checked out the Wikipedia article on iridescence, and there was a very comforting photo of a fly's wings that showed the same phenomenon. The photo's depth of field was amazing; the description referenced the 'photo stacking' of 7 images. That wouldn't work with lively bees, but with a more cooperative subject... I'll have to look into it.

Thanks again,
Ed

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David,

Thanks for your input. Excellent question re diffraction; I've wondered the same thing myself. I think for very small subjects at relatively high magnification, like this half-inch bee, the gain in perceived sharpness from stopping the lens down outweighs the loss in actual sharpness from diffraction effects.

Speaking of sharpness, I shot all of these bee photos as both 'fine jpeg' and NEF RAW. Zooming in on the two versions of each image, I find zero difference in sharpness between them, even though the NEF file is 3+ times the size. For this small sample size, jpeg appears as 'lossless' as NEF. Or, I'm not viewing the files correctly.

Ed

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Timeshifte,

Thanks for your reply! Consensus seems to be - as you pointed out - that moire is not the culprit. That's a good answer, since as I'm sure you know moire is a concern for the E version of the D800.

Regards,
Ed

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Ed, I'm far from an expert here, but I also tried to distinguish between NEF and fine JPEGs and I can't really see the difference. Of course, you can do things to a NEF that you can't do to a JPEG in NX2...

There certainly can be differences between NEF and JPG images - but they tend to manifest themselves in more challenging conditions, or when performing significant post-processing.

The first major difference is that a JPG has only 8 bits per channel, rather than the 12 or 14 bits of NEF files. As a result, NEF's can maintain fine gradations of tone in highlights and shadow areas much more readily.

The second thing to remember is that JPG is always a "lossy" format, because of the data compression applied. Whenever you open, edit and then re-save a JPG, image data will be lost. After a few iterations, you'll start to see big differences.

Having said all that, today's cameras have ever better JPG engines, and I'm quite happy to use that format for "holiday snap" type of images, or if I know I want quick results out-of-camera when shooting in kind lighting conditions

Brian
Welsh Nikonian
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So,would I be right in thinking that both are going to give you virtually the same image right out of the camera (to the naked eye), but that with NEF you can pull more out of the shadows and highlights in post-processing than with JPEG? Assuming that's a 'yes,' then if you process the NEF to tweak those shadows and highlights, then convert to JPEG, will you be losing anything significant when you convert it to JPEG? That's what I've been doing, but I don't have any pro uses or aspirations for my work. Mind you, I do want the absolute best image I can get, but it's as a challenging hobby. I don't even use my best camera for holiday and birthday shots.

>Mind you, I do want the absolute best image I can get

To meet that requirement, I would always shoot in NEF. Shooting JPG's, you may find yourself thinking "could this shot have been better?"

Brian
Welsh Nikonian
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Amen to that.

The differences are not readily seen on a low res monitor with a small display with restricted dynamic range so for many more casual images for web or small prints JPG as a storage and presentation medium is fine.
Printing with high resolution and wide color bit depth, you will see a difference provided a representative sample in both formats have minimal post processing. Every time you save the jpg file after any modifications or editing, the jpg loses data that can't be recovered.
If you are doing any work on a jpg file, do not edit the original, only use a copy of the original and save it as a new file name so that a minimum of lossy compression cycles will be used on the file. There will still be a minimum of two lossy compression's. Each cycle of compression really degrades the file so after a few edits, it is not suitable for printing in any sort of quality.
The 14 bit data recorded in RAW has much more information about color and luminance than the 8 bit JPG, since each additional bit doubles the data, RAW records a great deal in much finer steps in color or tone. The RAW file allows more extreme rescues or modifications can be performed without degradation of the original file, which is kept intact. Lossless compression of RAW files is just that, it loses none of the information whole reducing the size of the file in the compression process.
So the final presentation media is the determining factor as to whether JPG is good enough. Printing large or with high resolution with a printer and medium that an display the wider dynamic range, RAW is a must for the best quality.
Stan
St Petersburg Russia

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Example of moire' UN-Edited on my D800E 24-70 F2.8 - I find it in clothing:

Sample crop from portrait I took:





100% crop from his left shoulder area:





Another example from my 70-200 F2.8:





Moire' will look more like a rainbow effect if you run into it.... So hope this helps to show what to look for per say.

Chris

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Attachment #1, (jpg file)
Attachment #2, (jpg file)
Attachment #3, (jpg file)

Chris, many thanks. I would probably have missed these effects, especially on the shirt. Now I'll look more closely.

Assuming that you wanted to, is there an 'easy' way to eliminate this effect in post-processing?

Thanks,
Ed

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Stan,

Thanks for your reply. I will tell you that I'm comparing jpeg and RAW on a high-resolution, color corrected monitor. And zooming in to the pixel level I just can't tell the difference in sharpness between them.

However I understand what you're saying, and I've decided to always shoot jpeg+RAW, even though I don't yet know how to extract the maximum benefit from RAW. But that should be an interesting journey of discovery.

Regards,
Ed

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LR4.3 has a brush to remove the color moire' but it doesn't removed the pattern that is left behind in the shirt. There is a website that has a video that walks you though completely removing moire' in Photoshop but I haven't tried it to see if it works for me. Found it here:

http://vimeo.com/23508129

For me the color pattern is really the main thing that I am worried about as these patterns are very small in these example images and wouldn't likely be noticed by the average person that doesn't know that it's an "issue" per say.

Chris

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