beetle picture upload attempt

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robirdman
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Joined: Wed Dec 04, 2013 4:53 pm

beetle picture upload attempt

Post by robirdman »

Just an example of the procedure I was using before coming to this forum. I had the camera on a boom and would lower it over the subject. With a 500marco lens I would then shoot it at the smallest aperture. Here is a large beetle.

Clicklng on upload picture.
Now I got it.
Image
Last edited by robirdman on Fri Dec 06, 2013 4:12 am, edited 1 time in total.

robirdman
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Post by robirdman »

Another attempt. Click upload picture. nothing opens.

rjlittlefield
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Post by rjlittlefield »

It's a popup dialog. Check to see if you have popups disabled in your browser.

--Rik

robirdman
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Post by robirdman »

I've been looking in the browser settings without success, then tried to follow 2 different web directions to enable or disable popups, and both went to non applicable dead ends.

The first time I opened the upload picture box, browsed to the directory and selected the file I wanted upload and then got no further. After that the box's function ceased.

rjlittlefield
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Post by rjlittlefield »

I don't recall hearing of this sort of problem before. It sounds like the browser thread handling the upload popup got hung. That would explain why the first upload didn't finish, and now you get no response. The fact that it appeared the first time means it's not a popups-disabled problem. Alternatively it's possible that an errant mouseclick managed to hide the upload popup window behind other windows and now it just refuses to pop to top by itself.

The usual recovery path for browser hangs is to try exiting and relaunching the browser (which may fail due to the hung thread), forcing the browser to exit (using Task Manager "end process" or the equivalent depending on what operating system you're using), trying a different type browser (Firefox, Internet Explorer, Safari, Chrome, etc), and/or rebooting the computer.

By the way, this thread is out of place in the FAQ forum. After you've had a chance to reply, I'll move it to Technical Discussions.

--Rik

Chris S.
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Post by Chris S. »

Robirdman,

I suggest you try a test of running a browser without any add-ons. Not knowing what operating system you're running, here are instructions for Windows 7:

Start>All Programs>Accessories>System Tools>Internet Explorer (No Add-ons). This should bring up a session of Internet Explorer with no add-ons loaded.

In this very clean browser, can you upload your image? If so, the trouble is an add-on.

While trying a different browser is good advice that often works, it's also quite possible that multiple browsers on a computer are constrained by the same (or different) add-ons.

--Chris

robirdman
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Joined: Wed Dec 04, 2013 4:53 pm

Post by robirdman »

In preparation to restarting IE, I started closing its open links. Turns out I had maybe 40 or 50 as I kept going to different links in the forum and then checking other things such as ebay and products. I couldn't even see all the links as when I kept closing them there were more hidden along the bar. I had been afraid I wouldn't be able to find some of these place again, but didn't realize some were multiple times when I came back and were hidden in the row, not showing till others were deleted.
Anyway, after clearing out a whole lot, the upload link appeared. It was hidden. I uploaded the beetle again and then searched for the directions link again and found after opening more links. It is sitting waiting to be uploaded but nowhere to go, I guess because that post was finished. Maybe if I try to edit. If not start over again.

robirdman
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Post by robirdman »

So upload success with image added in first attempt post above. Mostly in focus, from one shot. How many stacks estimated to get it all sharp?
I am wondering about hard drive space after reading about the hundreds of shots for the blowfly. Do you keep them all?
I just bought an 8T drive partitioned to do 4T raid because my 3T archive and 3T backup were getting too close to showing the red overfill mark.

rjlittlefield
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Post by rjlittlefield »

...after clearing out a whole lot, the upload link appeared.
Thanks for the explanation of what went wrong. It's always nice to know, so that we can help the next person better.
...image added in first attempt post above. Mostly in focus, from one shot. How many stacks estimated to get it all sharp?

It depends on what you mean by "sharp". If you're happy with the in-focus areas now, and you just want that same level of sharpness to extend over the whole subject, then maybe you need only 2 or 3 frames. But if you want it to be as sharp as your lens will go, then you'll need a lot more, maybe 20 or 30.

In most focus stacking, a good measure of success is to have no "focus banding" -- no alternating bands of sharp and blurred.

To accomplish that goal, you need focus planes that are no farther apart than roughly the values that are shown in the tables HERE. For example at 1X, you'll have about 0.27 mm DOF when operating at effective f/11, or about 0.56 mm DOF when operating at effective f/16. If you're willing to stop all the way down to effective f/45 and live with that level of diffraction blur, then you can have 4.3 mm.

It's important to think carefully about those numbers. 4.3 mm at f/45 is 16 times larger than 0.27 mm at f/11. That sounds crazy at first thought: the aperture is only 4 times narrower, so where does 16 come from? The key is to realize that as you stop down, you are also implicitly increasing the size of the acceptable blur circle. As a result, the usable DOF increases by one factor of f-number due to the narrower cone of light, and also by a second factor of f-number due to your willingness to tolerate a larger blur circle. 4*4=16, and that's where the 16 comes from.

So, everything hinges on how sharp you need your images to be. You choose the aperture to give that sharpness, then the aperture setting and magnification imply the DOF and focus step size.

Most of the focus stackers here at photomacrography.net are detail seekers. We find the sharpest lenses we can, then we set them to their sharpest apertures which turn out to be pretty far open, and that results in shallow DOF that requires lots of frames to cover the subject.

The final images look great -- so great that we have to show 100% pixel peeps just so that somebody else on the internet can see how great they really are. Bear in mind, most of these images are so sharp that they would make 20"x30" prints that still look sharp even when held close.

Quite frankly, that level of sharpness is overkill for a lot of applications. If it's affordable overkill, no problem. But if you have a few thousand specimens that you're looking to document, then it's worth running through the numbers to see what the tradeoffs are.

Quite possibly your needs would be met better by stopping down farther and getting to use shorter stacks as a result.

Just be sure to factor in all your other costs, such as specimen handling, record keeping, and image post-processing. You may discover that in the grand scheme of things, you can have images that are two or three times sharper with only a fractional increase in the total time per specimen.
I am wondering about hard drive space after reading about the hundreds of shots for the blowfly. Do you keep them all?
I do, yes. Again, context is important. I shoot a relatively few stacks, going for highest possible quality, and because I also develop focus stacking software there is additional value in keeping source images for R&D purposes and so that I can reprocess as the software improves.

Among other people I know, some do save all their source images and some don't. Both strategies make sense. It comes down to trading off the cost of storing all the source images versus the cost (and often the impossibility) of reshooting the real subject if you wanted a better result at some later time. It's hard to get a good handle on most of those costs, so quite frankly there's also a lot of personality involved. Some people are just a lot more comfortable getting rid of stuff they might conceivably want sometime but probably won't.

--Rik

robirdman
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Post by robirdman »

I am confused.
In the first table it appears that the sensor shrinks as the field gets larger or vice versa. What does this mean?

Also even with this equipment there is a diffraction problem? I thought maybe that was on older or less expensive lenses, so I always use the minimum to get the most in focus. It would be sharper but less in focus with f16? How do you detect the diffraction?

I am mainly documenting a collection to get or verify identifications from photo online. Where the whole top image is insufficient, I would then go back and take more shots or close-ups of other areas. I am finding that just setting up for a single decent shot takes a lot of time. I think I did about 50 species over a period of days. I do need to streamline the process - cleaning and such. Preparing and removing remaining debris in Photoshop may take an hour for one image.

rjlittlefield
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Post by rjlittlefield »

robirdman wrote:In the first table it appears that the sensor shrinks as the field gets larger or vice versa. What does this mean?
I think you're misreading the table, but I can't tell how.

The table is designed so that you choose the sensor size and the field width, and the table tells you the magnification.

Reading down each column to keep sensor size constant, smaller field means larger magnification. Reading across each row to keep field size constant, larger sensor means more magnification. Reading diagonally to keep magnification constant, larger sensor means a larger field is covered.
Also even with this equipment there is a diffraction problem? I thought maybe that was on older or less expensive lenses, so I always use the minimum to get the most in focus. It would be sharper but less in focus with f16? How do you detect the diffraction?
I think you're confused between diffraction and lens aberrations. Better lenses have less aberration, and stopping down reduces most aberrations. But diffraction is an intrinsic problem that is due to wave properties of light. Even a perfectly designed and manufactured lens will suffer from diffraction, and stopping down makes diffraction worse. With most lenses there is a "sweet spot", a couple of f-numbers down from wide open, where these effects are balanced and the lens gives its sharpest image. Very good lenses can be sharpest wide open. See Aperture and lens effects on stacking for illustration of these effects. For a physics-level discussion, see What really causes "diffraction blur"?

One wrinkle in discussing diffraction blur is that with modern Nikon cameras and lenses, the f-number you set on the camera is actually the effective f-number, from which the camera determines the aperture diameter by taking into account the effects of magnification. In that case, when you set a constant number into the camera, the lens aperture actually gets wider as you turn the ring to increase magnification. You can check to see if this is happening by looking at the widest f-number you're allowed to set at various magnifications. If you're allowed to set f/4 at infinity focus but that shrinks to say f/8 at 1:1, then what you're setting is the effective f-number. On other cameras, and with other lenses on that same camera, you would be setting the lens aperture directly so that a setting of "f/4" would actually be f/4 effective at infinity focus, but would become f/8 effective at 1:1.
I am mainly documenting a collection to get or verify identifications from photo online. Where the whole top image is insufficient, I would then go back and take more shots or close-ups of other areas. I am finding that just setting up for a single decent shot takes a lot of time. I think I did about 50 species over a period of days. I do need to streamline the process - cleaning and such. Preparing and removing remaining debris in Photoshop may take an hour for one image.
This sounds like a situation where maybe you want to take a few extra minutes to shoot and process a deeper stack that was shot with a wider aperture to pick up some extra sharpness. That way instead of going back and shooting a close-up of some area, you may be able to get the same result by just loading up the high resolution stacked output and taking a crop of it.

--Rik

robirdman
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Post by robirdman »

I like that 'circle of confusion'. I feel I've been in one. A huge amount of new info to take in. Going back I see that on the first table my confusion was that the top of the table says sensor size. Usually a column heading indicates what is below, which I understand now is the magnification now, after rereading. Thanks for the clarification.
When you said the aperture gets wider when you increase magnification, did you mean just a larger number? The aperture get smaller as when set at 22 but reads 45, because the F numbers are reciprocals.

Now I am wondering how Photoshop's own stacking and focus blending might work for this project, as I just found the method.

I'm probably going to redo almost all again with a more thorough cleaning and without the labels, as leaving them on and trying to edit them out was the biggest mistake in trying to get a somewhat natural looking image. I just went ahead and shot way too many before finding out how long it would take to process.

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Post by rjlittlefield »

robirdman wrote:I like that 'circle of confusion'. I feel I've been in one.
"Circle of Confusion" is a standard term when talking about DOF. You'll find it as an input parameter for most classic formulas. But I take your point about there being a lot of new info to take in.
When you said the aperture gets wider when you increase magnification, did you mean just a larger number?
I assume you're talking about the part where I said "In that case, when you set a constant number into the camera, the lens aperture actually gets wider as you turn the ring to increase magnification. ".

In that case, no I really did mean wider, as is more mm wide. With certain Nikon camera+lens combinations, if you set "f/16", then at infinity focus the camera will tell the lens to use an aperture that's essentially 12.5 mm wide, but if you change focus to be 1:1, the camera will tell the lens to use an aperture that's 25 mm wide. Turning the ring to increase magnification makes the lens aperture get wider, in this example from 12.5 mm wide at infinity focus to 25 mm wide at 1:1. In both cases the "effective aperture" corresponding to the cone of light seen by the sensor will be f/16, but in one case that's a 12.5 mm aperture at 200 mm away from sensor, and in the other case it's 25 mm at 400 mm away from sensor.

You write "The aperture get smaller as when set at 22 but reads 45". That suggests to me that your camera+lens combination uses yet a third approach, where you set the aperture directly on the lens (200mm/22=9.09mm), and then the camera figures out that at 1:1 this really gives effective f/45 (9.09 mm at 400 mm from sensor, 400/9.09~=45).
Now I am wondering how Photoshop's own stacking and focus blending might work for this project, as I just found the method.
At low mag, your beetles may be pretty good candidates for Photoshop due to their generally smooth surfaces with no bristles or complicated overlaps.

However, I suggest reading "Image comparison of ZS and PS CS5 on deep high mag stacks" to see other possibilities you may encounter.

The market for specialist focus stacking software has only increased since Photoshop incorporated their version. There are good reasons for that. In brief, Photoshop's implementation works really well sometimes and fails badly at others, while offering a fairly low level of predictability and control.

See HERE, pages 50-52, for illustration with a surprisingly challenging landscape subject. Use your mousewheel to switch back and forth between "Result by Zerene" on page 50 and "Result by Photoshop" on page 51 to appreciate the differences. Page 52 shows the masks computed by Photoshop, which will explain why it doesn't do so well on that example.

BTW, after your next reply here, I will move this topic to Technical Discussions as previously mentioned.

--Rik

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