Zhongyi (Mitakon) Super Macro Lens (1 - 5x)
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If you are trying to compare the two images, they will not match -- different stitching algorithm will yield different result for SURE.
As for less CA, like I said before, if part of tile happen to be shot and stitched with most part in the center, then it will have less CA for this lens.
I did not add any saturation to the finished image, the only adjustment was adding 25% unsharp masking (I think I did it twice, so more than 25%), I think maybe my monitor is playing tricks on me again -- it tends to display with higher contrast and saturation.
My next test is to use APSC mode of the Sony A7 III so that most images acquired will have less CA overall, and maybe compare it with a 5x Mitty + 100mm tube lens in the same mode.
As for less CA, like I said before, if part of tile happen to be shot and stitched with most part in the center, then it will have less CA for this lens.
I did not add any saturation to the finished image, the only adjustment was adding 25% unsharp masking (I think I did it twice, so more than 25%), I think maybe my monitor is playing tricks on me again -- it tends to display with higher contrast and saturation.
My next test is to use APSC mode of the Sony A7 III so that most images acquired will have less CA overall, and maybe compare it with a 5x Mitty + 100mm tube lens in the same mode.
I think a truly telecentric lens will produce tiles that need no modification by the stacking algorithm, so I think all good algorithms should give the same result with such tiles. My experiment using Nikon MM telecentric objectives did not require any scale change or rotation in order to match tiles. I did the stitching manually in Photoshop so I could see what transformations were required.different stitching algorithm will yield different result for SURE.
I do not think the lens is a TRUE telecentric lens, this is why I added suggestion to them to TRY to make it more telecentric by moving the aperture (vs changing optical path)Lou Jost wrote:I think a truly telecentric lens will produce tiles that need no modification by the stacking algorithm, so I think all good algorithms should give the same result with such tiles. My experiment using Nikon MM telecentric objectives did not require any scale change or rotation in order to match tiles. I did the stitching manually in Photoshop so I could see what transformations were required.different stitching algorithm will yield different result for SURE.
With any algorithms, it is rather hard to get EXACTLY same result, ie, pixel to pixel match, when approaches are different.
In my algorithm, though still buggy, I do not see much rotation nor scaling. The algorithm is a simple one, my intention is to let user do a sweep scan (where the video was shot) and produce a preview. This is rather helpful for planar subjects before a full SnS stack. But looks like this feature will be dropped as it is too difficult to implement.
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Is telecentricity a desirable quality in a general use lens? I'd also expect the aperture needs to be smaller to achieve telecentricity, smaller than f2.8, so not a great move for marketing purposes.mjkzz wrote: I do not think the lens is a TRUE telecentric lens, this is why I added suggestion to them to TRY to make it more telecentric by moving the aperture (vs changing optical path)
BTW, what aperture did you use for the SnS?
I think it is a nice feature for making stacked scientific imaging, even when not stitching, because it allows accurate measurements that do not depend on the z-coordinate. This is of course why the major objective manufacturers make telecentric objectives.
I remember some discussions here about scale bars. Telecentric lenses resolve all those ambiguities.
I remember some discussions here about scale bars. Telecentric lenses resolve all those ambiguities.
I think it is, the more telecentric, the better. Whenever you have scaling factor not being one, no matter how good your stacking algorithm is, there ought to be some "guess work" (for example, when scaling up, interpolation will be used, this is just one example), and these "guess work" are part of computer generated, "artificial" ones, ie, in my opinion, these are distortions.ray_parkhurst wrote:Is telecentricity a desirable quality in a general use lens? I'd also expect the aperture needs to be smaller to achieve telecentricity, smaller than f2.8, so not a great move for marketing purposes.mjkzz wrote: I do not think the lens is a TRUE telecentric lens, this is why I added suggestion to them to TRY to make it more telecentric by moving the aperture (vs changing optical path)
BTW, what aperture did you use for the SnS?
So, yes, telecentricity is very important, particularly when stitching stacked images.
I used f/2 mark which seems to be the sweet spot of this lens.
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Yes, but what % of folks are doing stacked scientific imaging? My point is that the mfr is probably looking at the lens to replace the MPE65, so in this context is telecentricity a desirable property?Lou Jost wrote:I think it is a nice feature for making stacked scientific imaging, even when not stitching, because it allows accurate measurements that do not depend on the z-coordinate. This is of course why the major objective manufacturers make telecentric objectives.
Sorry, this might sound nitpicking , but I would characterize telecentricity as a property of an optical system. A feature sounds like something you can add instead of "being"?Lou Jost wrote:I think it is a nice feature for making stacked scientific imaging, even when not stitching, because it allows accurate measurements that do not depend on the z-coordinate. This is of course why the major objective manufacturers make telecentric objectives.
I remember some discussions here about scale bars. Telecentric lenses resolve all those ambiguities.
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What % of folks buying this lens are going to do Stack and Stitch? Probably < 0.1%. So indeed telecentricity may be important to you, but is it to the manufacturer, especially if it causes a reduction in performance for other purposes?mjkzz wrote: So, yes, telecentricity is very important, particularly when stitching stacked images.
I used f/2 mark which seems to be the sweet spot of this lens.
You mention f/2 but I think this is an f2.8 lens? Do you mean stopped-down 2 stops?
But I think this lens is so close, moving the aperture MIGHT work, so why not?ray_parkhurst wrote:What % of folks buying this lens are going to do Stack and Stitch? Probably < 0.1%. So indeed telecentricity may be important to you, but is it to the manufacturer, especially if it causes a reduction in performance for other purposes?mjkzz wrote: So, yes, telecentricity is very important, particularly when stitching stacked images.
I used f/2 mark which seems to be the sweet spot of this lens.
You mention f/2 but I think this is an f2.8 lens? Do you mean stopped-down 2 stops?
I set the aperture at f/2 mark on the lens.
You're right, that does sound like nitpicking to me. Anyway I think if one is assembling an optical system, telecentricity is indeed a feature that can be designed into the system if one wants. If we had two competing optical systems, one telecentric and the other not, I think it is quite natural to say that the telecentric system has a feature that the other does not have.Sorry, this might sound nitpicking, but I would characterize telecentricity as a property of an optical system. A feature sounds like something you can add instead of "being"?
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So this is actually an f/2 lens, not f/2.8?mjkzz wrote:But I think this lens is so close, moving the aperture MIGHT work, so why not?ray_parkhurst wrote:What % of folks buying this lens are going to do Stack and Stitch? Probably < 0.1%. So indeed telecentricity may be important to you, but is it to the manufacturer, especially if it causes a reduction in performance for other purposes?mjkzz wrote: So, yes, telecentricity is very important, particularly when stitching stacked images.
I used f/2 mark which seems to be the sweet spot of this lens.
You mention f/2 but I think this is an f2.8 lens? Do you mean stopped-down 2 stops?
I set the aperture at f/2 mark on the lens.
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But it also has limitations on size of objects being imaged. I'm not sure if the front lens is large enough for telecentricity across the full mag range, but if not this might be a problem. Plus won't the lens need to be stopped-down a bit to be telecentric?Lou Jost wrote:You're right, that does sound like nitpicking to me. Anyway I think if one is assembling an optical system, telecentricity is indeed a feature that can be designed into the system if one wants. If we had two competing optical systems, one telecentric and the other not, I think it is quite natural to say that the telecentric system has a feature that the other does not have.Sorry, this might sound nitpicking, but I would characterize telecentricity as a property of an optical system. A feature sounds like something you can add instead of "being"?