PF Photography: Tips, Tricks, & Photo Sharing

[Andre]

A neat idea to test the extremes, I tried the dining area for that,

(all shots converted RAWs from the defaults, no post processing)

First with the Tokina 12-24mm at 12mm (equivalent to 19mm FX format):

The aperture was 5.5 and it was focussed manually more in front to optimize depth of field as can be seen on the center crop and the little bottle down and slightly right off center.

Then from the same tripod position the 70-300mm zoom at 300mm (FX equivalent 480mm) F5.6 again:

The center crop is not too crisp, but that was to be expected.

-----

I also wanted to know if I should use the 100mm macro lens some more for shots that were taken with the 70-300mm. So I wanted to know how those two compared under the same condition, for that I made this shot, close at minimum range for the 70-300mm with both lenses (F6.7):

Interestingly you have to zoom to 90mm to get the same image as the 100mm macro. The reason for that is that the macro lens does not change it's length during focussing, so what it actually does, is changing its focal length.

Anyway, compare center crops of both lenses:

Can you tell, which is the better lens? I can't

Surprisingly, the 70-300 seemed to have produced the sharper result albeit by a tiny notch :uhh: Maybe the 100mm needs some micro adjusting

 

[Borek]

Based on the star images, I suspect my main culprit is mirror flap- the stars consistently got distorted into short lines, even for 1/10 second shutter speed- and the lines were always the same length and orientation

7.3 microradians, perhaps

 

[Andy Resnick]

A neat idea to test the extremes, I tried the dining area for that,

<snip>
Anyway, compare center crops of both lenses:
<snip>

Can you tell, which is the better lens? I can't

The upper image appears brighter and more vivid- is that an aperture difference?

7.3 microradians, perhaps

Good question- I'm not sure what the subtended angle is. Let's see: 800mm on a 35mm frame gives a total subtended angle of 2.5 degrees, and given the sensor format (6k x 4k, 7200 on the diagonal), each pixel subtends about 1.25 arcseconds (6 microradians). By my count, the 'fundamental' streak length is about 30 pixels, or 0.18 milliradians (0.6 arcminutes).

So there's a lot of room for improvement.

 

[Andre]

The upper image appears brighter and more vivid- is that an aperture difference?

Curious, isn't? However, everything was identical, including the flash settings. Yet he colors are clearly different. Here are both orginal jpg's with EXIFs, slightly higher compressed to limit filesize.

http://dl.dropbox.com/u/22026080/70-300.jpg
http://dl.dropbox.com/u/22026080/100.jpg

 

[d.smith292]

I have some pretty cool photos on my blog at

http://www.broughttofocus.wordpress.com

and at my art gallery at

http://www.etsy.com/shop/dsmith292

 

[Andy Resnick]

I have some pretty cool photos on my blog at

http://www.broughttofocus.wordpress.com

and at my art gallery at

http://www.etsy.com/shop/dsmith292

I like the contrast in a lot of your B&W photos (like 'Lively squirrel' and 'Hidden content', for example)- do you use a filter to boost the contrast (like an O56), or just use a B&W mode on the camera?

 

[d.smith292]

No, actually I don't use filters at all. I am hoping one day to upgrade to a much better camera, but for now I'm using a Canon Powershot a520 and adjusting the contrast on my computer. Thank you for the complement. Oh and I always shoot my photos in color and change them to black and white later. I do this just in case the color version looks better in the end.

 

[turbo]

Hi, Andy. The moon is out, so a couple of minutes ago, I shot this. 1600 ISO to minimize atmospheric refraction and (human) shake. 100-400mm Canon L lens at full zoom, hand-held (no bracing of any kind) and cropped hard. I got a tad of color-noise at that ISO, so I converted the image to grayscale, since the Moon is a pretty white-gray place. Not the same quality that I could get with one of my APO refractors, but not bad for strolling (limping, actually) out onto the back deck and making a snapshot. The moon is a pretty featureless (low contrast) place when it is nearly full, but check near the lower limbs.

 

[Andy Resnick]

Hi, Andy. The moon is out, so a couple of minutes ago, I shot this.

Nice!

I've been working with the 400mm lens today (and dodging raindrops)- with the teleconverter, the image is soft until I set the lens to f/8- then it's incredibly sharp (that is, an 800mm f/16 lens). Without the teleconverter, the image is much sharper always, and gets tack-sharp around f/4.

Consistently, any point-like 'sparkles' get rendered as short lines, always in the same orientation and length. This supports my idea of lens flap, but I won't know for sure until I can remotely trigger the shutter.

 

[Andre]

Another moonshot made around midnight last night. Hardware the 7D with the 70-300mm at full tele

Exposure manual trial and error, I ended up with this ISO 100 F6.7 Shutter 1/180

Raw processing: a tad more sharpening. contrast high tones priority and noise reduction off

100% size crop:

The glass keeps amazing me.

 

[Borek]

I planned to take a picture as well, but it was hazy. Seems like tonight can be better.

 

[drizzle]

WOAHHHH
Amazing.

 

[turbo]

Same 4-15 image of the moon, but with smart sharpening in Photoshop. A bit grainy after sharpening.

 

[Andy Resnick]

The weather was highly cooperative this past weekend, and I was able to spend time sussing out the 400mm. There's definitely a 'sweet spot' to use the lens- in terms of shutter speed, either < 1/60s or >0.5s overcomes the mirror flap issue, and > f/5.6 gives tack-sharp images.

Here's the full moon last night, 100% (sorry, it's a bit over 650 pixels on a side): This was taken at 400mm, f/11, ISO 100, 1/80s

[PLAIN]http://img25.imageshack.us/img25/9360/dsc6119.jpg

Looking carefully at the limb, you can see atmospheric effects- the atmospheric currents act like a lens, creating a 'mirage' kind of flicker. At 800mm, the effect is very pronounced (100% crop): 800mm, f/5.6, ISO 100, 1/80s:

[PLAIN]http://img849.imageshack.us/img849/1358/dsc61261.jpg

It was pretty cool to watch through the lens, even though it limited the ultimate resolution.

I was able to get an acceptable image of Mizar (300% cropped image): 800mm, f/5.6, ISO 6400, 1/80 s:

[PLAIN]http://img685.imageshack.us/img685/9362/dsc6134.jpg

I can tell it's a multiple, but perhaps not that it's a double binary. Atmospheric blurring is quite obvious here.

 

[iBOOM]

I really love the moon photos :O

 

[turbo]

I really love the moon photos :O

They are the first real astrophotos that most amateurs could make during the age of photographic films. Sometimes, purists got wrapped up in trying to capture fainter and fainter stuff, so Moon photography fell out of favor, especially since the extra light would wash out faint details on long-exposure astrophos of galaxies, globulars, nebulae, etc. Now, technology allows photographers to take Moon shots as snapshots. That's a pretty good thing. The Moon is our closest neighbor and it changes from night to night. You don't have to set up a $$$$ telescope and accept washed-out astrophotos of faint objects on nights when the Moon is up. It took me probably 30 seconds total to grab a couple of snapshots.

 

[Andy Resnick]

It always feels good to solve a problem. Here's a 100% crop taken through the 800mm with a shutter speed of 1/6s (10-second delay) of the label on a nitrogen tank in the lab (from across the room):

[PLAIN]http://img98.imageshack.us/img98/3740/dsc61401.jpg

The delay allows all transient vibrations to dampen out, but when the mirror comes up for exposure, the induced vibrations cause what you see above. 1/6s is about the worst-case scenario: long enough to really capture the vibration, and short enough to *only* capture an image while everything is moving. The workaround was to use either shutter speeds very fast or very slow- either using the lens wide-open with very high camera gains (ISO) to get the exposure time down, or use very high f/# to force long exposure times. Both introduce restrictions- long exposures mean the subject has to be motionless, while high ISO introduces a lot of noise and using the full aperture of the lens also maximizes the aberrations.

Adding the $9 remote shutter results in this image - again, 1/6s exposure, using the mirror lockup option and waiting 3 seconds between the mirror lock and exposure:

[PLAIN]http://img808.imageshack.us/img808/2161/dsc6141.jpg

I don't think the improvement could be any more dramatic.

 

[Andre]

Nice work, Andy. I knew about that problem too and I use a remote as well, locking the mirror, using the life view mode. Etc.

Recently I changed studio work by using the laptop as remote 'wired' control. It also locks up the mirror, ad it stores the image, where it should go anyway, directky on the computer.

 

[Andy Resnick]

Nice work, Andy. I knew about that problem too and I use a remote as well, locking the mirror, using the life view mode. Etc.

Recently I changed studio work by using the laptop as remote 'wired' control. It also locks up the mirror, ad it stores the image, where it should go anyway, directky on the computer.

Interesting idea- I don't know if I can computer-control the Sony, but there's a variety of ports on the body... I'm finally getting a dedicated TB hard drive for my photos, in any case.

Also- I very much enjoyed the museum pics. Your country is considerably more picturesque than Cleveburg.

 

[Marzena]

Passiflora (also known as the passion flower or passion vine) bloomed today on my window sill:

Center of the flower - close-up:

 

[Andy Resnick]

Passiflora (also known as the passion flower or passion vine) bloomed today on my window sill:

very nice!

 

[khemist]

oh shiza can't believe I just found this thread.

my flickr: www.flickr.com/hoxiephoto

I update it as often as I get film developed!

Some examples:

lines by Hoxie Photography, on Flickr

the rock by Hoxie Photography, on Flickr

the can by Hoxie Photography, on Flickr

 

[Andy Resnick]

More fun with filters: I have a bunch of excess fluorescent filters left over from upgrading the microscope, and the results I got last week with the BG3 filter motivated me to try and use them. I seem to get decent results using bandpass filters at the extremes of color vision- center wavelengths shorter than 440 nm or longer than 650 nm- even very narrowband filters in the green-orange range excite multiple types of cones, so those monochrome images don't look much different than a (colorized) black and white image.

Hopefully this week or next I'll be able to measure how sensitive the Exmor is to different wavelengths (I'm not sure the bandpass values of the Bayer filter are standardized) to get an idea about how far out I can go. Some cameras (and independent repair guys) can remove the IR cut filter, but I'm not doing that. Ditto the UV: I'm not sure how deep the lens will pass, and I'm not about to take sandpaper to my lenses:

http://www.naturfotograf.com/uvstart.html

The image I submitted in this week's contest was taken with a excitation filter used for blue/violet excitation (436 +/5 nm, I think I quoted the FWHM incorrectly) at night- Hg lamps can be seen, but Na cannot. This one I took during the day- it was very overcast, but the open sky peeked through now and then:

[PLAIN]http://img806.imageshack.us/img806/3996/dsc6235.jpg

The red color is from (I suspect...) "blooming", which is a digital sensor phenomenon that occurs when the pixel wells are not fully zeroed out during a read- excess charge 'leaks' into neighboring pixels in the column.

http://learn.hamamatsu.com/articles/ccdsatandblooming.html

Becasue of the Bayer filter, the neighboring pixels are different colors, so the camera interprets the light as activation of the green/red pixels.

I also got some promising images using a 380 +/ 10 nm filter, but for various reasons the images are not worth posting here. Once I get a more reliable mounting scheme, I'll post a few.

 

[Andre]

I entered this one in the contest 'flowers for fukushima'. The orchids come from the local windowsil.

Used the 100mm at 2.8 aperture for shallowest depht of field. Unfortunately my 50mm f1.8 lens is broken after a fall :grumpy:
Obviously the exposure is a real challenge, so I just took several shots in manual, each time checking the saturation of the white, it's a function on the camera, making pure white flashing, the idea is to minimize that, allowing only minor portions of pure white.

So in the bright sunlight that came down to 1/3000 of a second, but almost all the white has detail

 

[Borek]

Taking a picture of white flower petals so that there is a texture visible is tough, usually it looks just boring flat. Nice effect.

 

[Andy Resnick]

I entered this one in the contest 'flowers for fukushima'. The orchids come from the local windowsil.

[]
Obviously the exposure is a real challenge, so I just took several shots in manual, each time checking the saturation of the white, it's a function on the camera, making pure white flashing, the idea is to minimize that, allowing only minor portions of pure white.

So in the bright sunlight that came down to 1/3000 of a second, but almost all the white has detail

That's exactly what I do as well (same process for the blacks).

 

[Andre]

Also being busy in the yard, I found some lillies of the valley today, modestly tucked away somewhere in a corner (using the same exposure method):

Remember the orchid from this post?

... ..with both lenses (F6.7):

Well this is how it looks now;

This time I "exposed to the right" and then processed the RAW back to normal. That should take care of some of the noise

 

[Andre]

For some reason, I wondered how an ant would see a lilly of the valley:

100% crop:

 

[Andy Resnick]

Finally- a sunny day. I took the 400mm to the top of a parking garage to get a clear view of the city and then also down by the lakefront to get a few shots of the Terminal Tower:

http://en.wikipedia.org/wiki/Terminal_Tower

Here's a shot at 400mm, f/8, ISO 100, 1/160s

[PLAIN]http://img836.imageshack.us/img836/5038/dsc6587y.jpg

And then at 800mm f/16, 1/60s:

[PLAIN]http://img807.imageshack.us/img807/2146/dsc6591.jpg

and a 100% detail showing a tiny little observation room which I *have* to figure out a way to get into:

[PLAIN]http://img7.imageshack.us/img7/3082/dsc65911.jpg

Just like wideangle lenses distort perspective, telephotos also distort perspective, but the other way; parallel lines remain parallel, removing depth information. For the tower photos, it appears that I am (nearly) at the same height as the subject when in fact it is about 500 feet above me. Angled surfaces appear flattened as well- here's another top of an office building:

[PLAIN]http://img844.imageshack.us/img844/6278/dsc6592u.jpg

The side facing me appears vertical, when it is actually angled in- the overall roof shape is a pyramid.

Here's why telephotos are used for other purposes- this is a 100% crop from 1/2 mile-

[PLAIN]http://img856.imageshack.us/img856/9611/dsc6593.jpg

It's possible to see the individual slats in the blind.

Finally, here's a shot of the "5 mile crib"- the source of Cleveland's water supply. It's about 3 miles from the shoreline and 5 miles from me:

[PLAIN]http://img859.imageshack.us/img859/5762/dsc6579m.jpg

The image is actually quite sharp- the image displays "shimmer"- thermal currents in the air, caused by the sun warming the ground and water. Here's the 100% crop:

[PLAIN]http://img405.imageshack.us/img405/166/dsc6580t.jpg

I'll have to try this again on a calm day.

 

[khemist]

Why do you get that vignetting? Are you using a crop sensor lens on a full frame camera?

 

[Andy Resnick]

The vignetting is due (most likely) to the lens adapter; I have a full-frame camera (Sony a850) and the lens is a Nikkor 400mm f/2.8 ED-IF. The Nikon-Sony adapter has a small lens to line up the image planes correctly, and (so I'm told) use of long focal length lenses can cause vignetting. I don't get vignetting with either the 15mm or my old 50mm Nikon lenses.

 

[Borek]

This is not exactly photography, but close.

I did some testing to check what is quality of 1080p video shot with EOS7D - and results are disappointing. Basically my line of thinking was - if the sensor and lens are able to produce sharp images at the over twice higher than needed resolution, HD video shot with the camera should be crisp sharp. But that's not the case. Either it is a matter of the scaling algorithm, or of the codec used, but the image is very soft and looks like 720p scaled up (or even worse).

I put the camera on the tripod, shot some video and took a picture from exactly the same place, not changing anything (camera focused before the test and AF switched off to avoid any surprises). Then I used avidemux to export a first frame from the video and rescaled - without sharpening nor any other tricks - the single picture taken with the camera. See below. Video on the right, picture on the left, this is crop from the middle down part of the view.

This is whole frame, just to give you some idea:

Nasty surprise I must say. I understand it is NOT a camera, but I hoped for more :grumpy:

 

[Andre]

I wonder about the performance of other cameras and not sure if you expect too much. Consider the writing speed and the amount of the data for instance. Maybe they needed to compromise on the compression algoritm causing a reduced amount of data.

Maybe I shuld try that too.

 

[Borek]

I wonder about the performance of other cameras and not sure if you expect too much. Consider the writing speed and the amount of the data for instance. Maybe they needed to compromise on the compression algoritm causing a reduced amount of data.

Could be - but if my calculations are right video is saved at about 44-45 Mb/s (4GB, which is a maximum file size supported, gave 12'35.6" or 755.6 sec video, 4*1024³*8/755.6/10⁶ = 45.5 Mb/s), which is more or less in the range of the Blue-ray bitrate. If anything I suspect the chip is not capable of fast compression, as it wasn't optimized for that.

 

[AlephZero]

I put the camera on the tripod, shot some video and took a picture from exactly the same place, not changing anything (camera focused before the test and AF switched off to avoid any surprises). Then I used avidemux to export a first frame from the video and rescaled - without sharpening nor any other tricks - the single picture taken with the camera. See below. Video on the right, picture on the left, this is crop from the middle down part of the view.

This is just speculation (the last "serious" video stuff I did was long ago on 16mm film) - but there are different requirements for "good video" compared with stills. For example you want relatively long exposure times to get realistic motion blur, not pin-sharp images. Animated movies with pixel-sharp images tend to create "flicker" when things move.

On film-based cine cameras the shutter speed was fixed at half the frame rate - i.e. 1/48 sec for standard movies - hence the hassles with movie lighting, because the f-stop was the only camera setting you had to play with. Changing to different speed film stock could introduce color matching problems.

Compare the reflections of the trees in the water, which is obviously moving - it's not so clear if there was any wind moving the vegetation.

I would guess that digital video cameras try to emulate the same behavior as cine film, since human vision works the same way whatever the source of the image.