Details, DP2M and Pixel-Peeping ...

Started 2 months ago | Discussions thread
xpatUSA
OP xpatUSA Forum Pro • Posts: 15,549
Re: Details, DP2M and Pixel-Peeping ...

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:

-- hide signature --

Ted

 xpatUSA's gear list:xpatUSA's gear list
Sigma DP2 Sigma DP2 Merrill Panasonic Lumix DMC-LX7 Panasonic Lumix DMC-G1 Sigma SD15 +17 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow