Physics Forums photography thread and image sharing

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tried it again but now with artificial light under controlled conditions. The difference between CD in focus and reflexions in focus is always some 30-40mm. It appears that the reflective surfaces acts as miniscule convex mirrors creating an imaginairy subject about that distant behind the CD.

I'll upload some in a while.
 
Three spotlights were positioned to the right, creating the three beams as reflexions

With the CD in focus at the minimum distance of 31 cm (1:1 with the 100mm macro lens, F11):
Close-up of the edge of a compact disc on the left, with bands of red, orange, yellow, green, blue and magenta light streaking horizontally across its reflective surface.


with the reflections best in focus with the focus ring showing 35cm distance (camera unmoved on tripod).
Three women in gold and silver swimwear pose side by side in a desert landscape with yucca plants, dead branches and rocky mountains behind them; the watermark reads fhm.com.


(note that the apparent/virtual zoom changes with change in focus distance)
 
This is a though one to take.

Close-up of a black cat's face showing two glowing yellow-gold eyes with dark pupils, with fine fur visible around them.


The focussing system refuses to work on all that black, so that had to be done manually and guess what Gizmo does when you hover around him with a big camera close to his face.

Anyway, it's entered in the challenge "yellow"

Drizzle, you can download again.
 
Andre said:
Three spotlights were positioned to the right, creating the three beams as reflexions

With the CD in focus at the minimum distance of 31 cm (1:1 with the 100mm macro lens,

with the reflections best in focus with the focus ring showing 35cm distance (camera unmoved on tripod).


(note that the apparent/virtual zoom changes with change in focus distance)

Just tossing out ideas, what happens when you focus to infinity? The diffraction pattern should still look sharp since diffraction picks out specific angles. And, where was the light(s)- how far from the lens? Were you perhaps imaging the lights in the second photo?
 
Andy Resnick said:
Just tossing out ideas, what happens when you focus to infinity? The diffraction pattern should still look sharp since diffraction picks out specific angles. And, where was the light(s)- how far from the lens? Were you perhaps imaging the lights in the second photo?

The last is the most likely, appartently the distorted imaginary images of the lights are a few centimeters behind the CD, when the focus is distinctly sharpest. The actual position of the three spotlights was some 15 cm to the right. At infinity setting everything is blurred.
 
Also made this one that evening:

Waves crashing against the dark vertical pilings of a pier, throwing up white spray and foam lit warm gold by low sunlight.


It's entered in the week challenge here.

http://masters.galleries.dpreview.com.s3.amazonaws.com/923334.jpg?AWSAccessKeyId=14Y3MT0G2J4Y72K3ZXR2&Expires=1297976772&Signature=MGTqZqzipdf5DpqZC0ag%2b90nmAg%3d
 
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The challenge is conceptual photography, for instance expressing a word that's not clear from the picture

So I entered this:

Close-up photo of a copper-coloured 1 euro cent coin on a white background, showing the large numeral 1, the word EURO above CENT, and the map of Europe on the globe design.


But which word is implied??
 
Here's some more shots from the mill the day after the 35W collapsed..
Street scene of a concrete parking structure on the left, a white police SUV driving on the road, traffic signals, a traffic cone and a barricade on the right, and tall beige buildings in the background under a clear sky.

Old stone grain elevator building beneath a yellow-lit GOLD MEDAL FLOUR sign on its tower, with a modern glass-and-brick structure and office block beside it under a clear blue sky.

Curved dark blue glass building with large black-and-white portrait photographs of three men mounted on its lower facade, surrounded by low shrubs and two people walking on a path.

Photo of a concrete arch bridge over a river with a collapsed green steel truss span hanging down into the water beside it, trees and city buildings behind.
 
Nice, redpenguin, I really like the photo you entered in the contest, and also the one of the same subject here, particularly, as well.
 
Since we had a snow day today, I worked on photographing a glass bowl. Nothing fancy- just a pressed-glass pattern. I had a blindingly white background (snow through a window), and took two sets- one backlit with the snow, and the other side-lit using the 85mm f/1.4. The images are 100% crops. I wanted to capture the diffractive effect of glass, and with my eye I could barely make out faint rainbows. Well:

[PLAIN]http://img88.imageshack.us/img88/912/dsc4386.jpg

[PLAIN]http://img132.imageshack.us/img132/9322/dsc4384v.jpg

[PLAIN]http://img573.imageshack.us/img573/3274/dsc4391e.jpg

[PLAIN]http://img638.imageshack.us/img638/3564/dsc4390t.jpg

These are unprocessed, and look a kajillion times more vivid than by eye. The first pair of images are backlit, and show that stepping down the aperture (f/1.4 top, f/18 below) increases the vividness of the color. The next two are sidelit, same apertures, and show that in this case, stepping down the aperture increases the contrast, but the vivid color is always present.

My thinking is that shooting glass (or ice, or water) is fundamentally different than shooting opaque objects- water and glass don't absorb the light, only scatter it, and so photographing glass objects is a lot like photographing a light source directly: extreme changes in contrast, etc. I guess the message here is that shooting with as small an aperture as possible will help bring out any rainbows present.
 
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Andy Resnick said:
These are unprocessed, and look a kajillion times more vivid than by eye.

"Unprocessed" or "not processed by me after it was automatically processed by the camera" :-p
 
I have a problem here:

Side-by-side 1:1 crops of a matchbox-style label showing the printed text "Atlas motyli" upside down, with a torn green top edge and a dark label reading "ypady" partly visible.


Same prime lens (100mm 2.8L macro), same ISO, both pictures taken from the tripod standing in both cases in exactly the same position, with the same external flash, distance about 2 meters, ISO 100, 8.0/200 - the only difference is a body. One is 400D other is 7D. Both crops 1:1. "Standard" picture mode in both cases (which means slight automatic sharpening).

7D is much less sharper. I would say surprisingly less sharper. Does it mean it is defective? I have no idea how they should compare, but I don't like what I see. From the 1:1 crops Andre posted I felt like the image should be crisp sharp, but it is obviously not a case.
 
Yes that's clearly not good.

This is a 100% crop (albeit fully sharpened with dpp)

Close-up macro crop of a copper-coloured coin's rim and field, showing a partial letter O, part of a letter or design element, and a small star-shaped device with fine reeded edge detail.


of this 1:1 shot with the 100mm non-L lens on the 7D.

Close-up of a copper-coloured 1 Euro cent coin on a white background, showing the large numeral 1, the word EURO above CENT, and a globe of Europe with stars and diagonal lines.


For better benchmarking you could use the test pictures of dpreview,in any test, for instance:

http://www.dpreview.com/reviews/PanasonicDMCGF2/page18.asp

Scroll down to the 4 crops with coins visible, select any camera you want in the pull down menu and compare. You can also download the full shot from that.

Incidently, the concept of this particular picture was "magnificent" or 'magnified cent'
 
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Borek said:
Does it mean it is defective? .

Obviously the result is not right but it could be a focus problem. How stable is the tripod? I see that my tripod is not stable enough, so I shoot using remote control in the life view mode (using manual focussing), so the mirror is already up.

The problem could also be the image stabilisation fighting the tripod. IS should be off on the tripod. Furthermore, it could be a calibration problem of the focussing. make an oblique picture of a yardstick, noting the exact focus point and see if there is a shift in focus. The 7D allows for individual lens focussing adjustments (menu C.Fn III 5). One of the reasons why it's so expensive.
 
Andre said:
Obviously the result is not right but it could be a focus problem. How stable is the tripod? I see that my tripod is not stable enough, so I shoot using remote control in the life view mode (using manual focussing), so the mirror is already up.

1/200 sec and a flash, that shouldn't be a problem. But just in case pictures were taken with 2 sec self-timer to avoid shaking.

The problem could also be the image stabilisation fighting the tripod. IS should be off on the tripod.

And it was off, forgot to state it in the first post. But at short times it is not that important, it becomes an issue when taking tripod pictures with longer times, like 0.2".

Furthermore, it could be a calibration problem of the focussing. make an oblique picture of a yardstick, noting the exact focus point and see if there is a shift in focus.

That's the only thing that remains to be checked. DOF is about 8 cm in front of the books and 8.5 cm behind, book that lies flat is less than 2cm behind the fronts, so there is a little bit of error margin. I have spotted problem using other lens, so I am afraid it is not lens related (edit: or it will be a problem with all lenses). But I will check.
 
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Right it's indeed beginning to look like a camera problem, although the focussing may be off for all lenses by miss management of the microadjust menu. But if that doesn't help to get something crisp and clear, then you run out of the options.
 
Are you sure? After selecting the adjust, you enter the function with the info button.
 
I am sure - they were disabled, I have played with the settings, then cleared data and disabled again. Now I am trying to take a picture with focusing in live mode, from what I understand it focuses using max contrast, not phase detection, so should be more accurate for not calibrated lenses. Trick is, batteries in my flash are almost dead and it takes forever.
 
Two stacked photos of the same spine of a green hardcover book titled "Atlas motyli Polski" printed upside down, with dark book spines and a pale green patterned book beside them.


Everything else as before, upper part - 400D, lower part - 7D with live focusing.

Thanks for pointing me in the right direction.
 
Borek said:
I have a problem here:

Same prime lens (100mm 2.8L macro), same ISO, both pictures taken from the tripod standing in both cases in exactly the same position, with the same external flash, distance about 2 meters, ISO 100, 8.0/200 - the only difference is a body. One is 400D other is 7D. Both crops 1:1. "Standard" picture mode in both cases (which means slight automatic sharpening).

7D is much less sharper. I would say surprisingly less sharper. Does it mean it is defective? I have no idea how they should compare, but I don't like what I see. From the 1:1 crops Andre posted I felt like the image should be crisp sharp, but it is obviously not a case.

Interesting. I found this:

http://www.dpreview.com/reviews/canoneos7d/page21.asp

Which compares the 7D to the 50D. There is a clear difference in sharpness (the 7D comes out sharper), but it's not clear how much is due to in-camera processing.
 
KrisOhn said:
Since I've gotten my camera and my primary interest in photography is astrophotography, I thought I'd post some of my first astro images here. I do know that there is a thread in the Astronomy forum dedicated to Astrophotos, but I feel these are better here.

All of these photos were taken from my home, a small farm in south eastern Saskatchewan, where the skies are about a Bortle 3. The photos were taken with a non-tracking tripod, ISO 1600, exposure times from 10-30 seconds, with the Canon T2i Kit lens, 18-55mm.

No processing has been done on the photos either(other than what my camera does itself); I am not too good at stuff like that yet.

Very nice! I'm jealous of the clear skies and good seeing.
 
Andy Resnick said:
Interesting. I found this:

http://www.dpreview.com/reviews/canoneos7d/page21.asp

Which compares the 7D to the 50D. There is a clear difference in sharpness (the 7D comes out sharper), but it's not clear how much is due to in-camera processing.

Thanks, I have seen this comparison, I was just on able to find it fast (while playing with tripod/lenses/three cameras and two computers). That was one of the reasons I was so badly surprised by the low quality of the pictures.

PS I have abused my superpowers and undeleted your post - it is perfectly on subject!
 
KrisOhn said:
Here is a crop of the Mizar-Alcor system from the photo above.
Night sky photo on a black background with scattered faint stars and a small cluster of three or four brighter points near the centre.

I am no longer able to see them both with a naked eye. I am afraid of checking if I can see them in my glases