Details, DP2M and Pixel-Peeping ...

Started 2 months ago | Discussions thread
xpatUSA
OP xpatUSA Forum Pro • Posts: 15,556
Re: Details, DP2M and Pixel-Peeping ...

docmaas wrote:

The same rock from the same perspective in full res might have been beneficial.

My shoulders are slumping with the sense that I've still failed to illustrate my main point correctly. However,  in answer to the above:

1) It was the same rock in each shot.

2) When stepping closer to shoot the rock, rather than the truck, it's perspective changes by definition .

3) My monitor is only 1920x1200px. Therefore my DP2M is normally set to low res: 2336x1568px.

An image is the sum of lots of factors, one of which is the number of pixels that capture any particular part of the image. Here the rock is captured by and limited in appearance by the number of pixels used to capture it. More pixels will allow for finer gradations in the appearance of the rock. I once saw the walls of the grand canyon used an an example of fractals. Increasing resolution showed how the subset of a larger chunk of the canyon revealed similar appearances of the larger chunk to the smaller chunks that made up that larger chunk. In a similar way more pixels can reveals subtleties fewer pixels cannot. If the whole of the rock is viewed at a certain level the eye is incapable of seeing the differences in resolution and one image appears just as good as the other. However the closer one looks the more the differences become visible in an image rendered with more pixels than one with fewer.

My own opinion, stated heretofore many times is that our brains differ and just like some people are genii in different fields due to inborn talents, some people are capable of seeing differences in images that others do not and perhaps cannot see also due to inborn abilities. Quite often these differences seen by those so cursed or blessed fall into the "there's no there there" world of inadequate tools to make the differences visible to those who don't sense them. Pixel level examination quickly loses itself as magnification grows the sought to examine image disappears into blocks of pixels that are only subtly different and seemingly incapable of making the differing observations of the whole image believable to those who don't have the natural ability to see them. Yet there are a pareto portion of those of us who do.

These differences appear throughout photographic fora often in conversations about micro contrast and other nebulous terms. There is something there but not everyone can see it.

Quite so. You might find this interesting:

http://filmicworlds.com/blog/visual-acuity-is-not-what-the-eye-can-see/

Another example of not everyone being able to see the same way is two image 3d viewing. https://www.youtube.com/watch?v=zBa-bCxsZDk I can't do this, I suspect because of my amblyopia discussed in other threads about eye dominance, but a lot of other people can. There use to be viewers in the library when I was in school that were built on this technique to present classical images in 3D. They always just looked like two blurry images to me.

xpatUSA wrote:

richard stone wrote:

xpatUSA wrote:

We talk about "detail" a lot in this Forum, perhaps because the Foveon is quite good at recording said detail.

I often wonder what "detail" is. In my own mind, detail is objects no smaller than one pixel at the sensor. My DP2M has a 5um pixel spacing and a 30mm focal length lens but how does that translate to objects in the scene? By which I mean that a leaf shot at minimum focusing distance is hardly a "detail" - but that same leaf shot from a mile away is beyond even the resolution of the Mighty Merrill.

Easy enough really, if we now talk about angles. The DP2M pixel at 30mm subtends an angle of about 0.6 minutes of arc, i.e. 0.1666 milli-radians (mrad). On the other side of the lens, i.e. in the scene, such a detail is easily calculated. An object 1 meter away will be 0.167mm large, 100 meters away the same 1-pixel detail will be 16.67mm large. Piece of doddle.

Although I have a DP2M, shooting anything with such detail is quite a challenge for me such that I find it necessary to go beyond 100% zoom in post to make sure my shots are at least half-decent. Of course, others here are so good at capturing "detail" that they need no such assurance and they cannot understand why I pixel-peep even at 100%.

So, in defense of pixel-peeping, I took a virtual shot of small piece of virtual mesh with exactly one-pixel dimensions with a virtual DP2M. Here is that virtual "shot":

So, how "good" is that mesh detail? Anybody?

No peeping now, y'hear? - but feel free to use a real magnifying glass on your monitor ...

More to come later ...

I must admit to being somewhat puzzled by this post. I don't take pictures of "details." There are generally details in the pictures I take, of course.

I understand your puzzlement. I must have failed to make it clear that I use pixel-peeping only for the checking of image quality, NOT as a means to "take pictures of details".

By way of illustration, I went outside and shot my truck in low-res:

OOC JPEG, FastStone Viewer:

No editing, no re-sampling, nut'n.

Looks "OK" bearing in mind it's a picture of the truck, not the shrubbery or grass.

Now I look at 400% to check image quality:

I see general softness and a really poor rendition of the rock which "just happened" to be lying there. Based on viewing at 400% I'd say the whole image is a failure ... which was not obvious at 100%. Had I looked at someone else's shot and posted a 400% crop with similar comments - it would not be unusual to get a huffy response. I have a vague memory of someone's 'boat on the beach' Quattro shot, hmmm ...

Obviously, a picture of an actual detail would look a bit mo' better:

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Ted

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