PF Photography: Tips, Tricks, & Photo Sharing

[Borek]

What camera do you use? And what flash? While my old flash is probably not capable of very short flashes, it has something called HS mode, which can be used with very short shutter times (shorter than the typical sync time). If memory serves me well when using HS mode I am limited only by the camera shutter. Can yield better results.

 

[KrisOhn]

I use a Canon 60D, the lens I used for that was a Sigma 17-50 f/2.8 at 50mm f/20. The flash is a Vivitar Auto Thyristor 2800, its old enough that I can't use it as an on camera flash on my 60D, it came with a Minolta X-700 I use for film photography. The technique I used to shoot this uses long shutter times, I used a 2 second shutter time to shoot that. You set up your equipment in a very dark room, and then using a long shutter time, you flash your subject during the exposure, creating an apparently very fast shutter speed. I'm not entirely sure how to calculate the apparent shutter speed, I don't know much about flashes, especially this one I'm using, but I estimate the flash would make it at least 1/10000 sec. This has a significant advantage of doing this by using the actual shutter, since you get fast shutter speeds, with enough light. If I were to attempt this without using strobist techniques, I could only achieve 1/8000 sec shutter speed, and I would need to get the subject lit appropriately or else suffer massive sensor noise.

 

[Andy Resnick]

I know you have some long lenses, I would love to see what you can do with this technique!

I'd be interested to try this method- is there an essential difference between this and 'normal' panoramic stitching? I can see the creative options by controlling the plane of focus, especially to simulate an 'anti-Scheimpflug' effect.

For example, I'd like to compare a stitched image produced with my 85mm to a single image (of the same field of view) taken using my 15mm lens. After the weather gets warmer, of course..

 

[KrisOhn]

I'd be interested to try this method- is there an essential difference between this and 'normal' panoramic stitching?

There isn't, the only difference is that most panoramas have very wide focal planes, where as with these shots, you want a very shallow plane.

For example, I'd like to compare a stitched image produced with my 85mm to a single image (of the same field of view) taken using my 15mm lens. After the weather gets warmer, of course..

I would be interested to see this comparison as well, I believe that if you keep the aperture constant, the 15mm lens wouldn't be able to reproduce the same image. But if you could change that, say have an 85mm lens at f/2.8, then a 15mm lens at f/0.5, then you might be able to get a focal plane small enough to reproduce it.

 

[Borek]

I estimate the flash would make it at least 1/10000 sec

It probably depends on the distance from the object, doesn't it? Or is it working in the "full flash, no metering" mode?

 

[KrisOhn]

It probably depends on the distance from the object, doesn't it?

I'm thinking about this and I don't think it should. The apparent shutter speed will be determined by the time the flash burst starts and ends, which should remain constant independent of distance. The only thing distance would determine is the start time at which the object becomes illuminated. A more powerful flash should be able to put out more light in a smaller fraction of time, therefore reducing the exposure time.

 

[Borek]

Flashes vary amount of emitted light by changing the pulse length. At last some early models worked by switching off after they were hit by the reflected light, so their pulse length was somehow proportional to the object distance. That means it was shorter for close objects.

Doesn't mean your flash works this way, but checking won't hurt.

 

[KrisOhn]

Flashes vary amount of emitted light by changing the pulse length.

Is this standard for all flashes? I'm just curious if they do this rather than varying intensity as well.

At last some early models worked by switching off after they were hit by the reflected light, so their pulse length was somehow proportional to the object distance. That means it was shorter for close objects.

That's interesting, and good to know, I might get a chance tomorrow to do some more water pictures, I'll try to test this by varying the distance.

 

[Borek]

Is this standard for all flashes? I'm just curious if they do this rather than varying intensity as well.

As far as I know most flashes just vary the time.

But then, what I know is definitely limited.

 

[KrisOhn]

The Vivitar flash I was using does indeed use a light sensor that detects the reflected light. I haven't tested this yet, but I've found its manual. While the manual doesn't explicitly say that it uses this kind of technology, from reading it, you get a sense that this is what it uses. It also states that the maximum flash time is 1/2000 sec, the minimum being 1/30000 sec.

 

[Borek]

the minimum being 1/30000 sec.

Sounds good, doesn't it?

 

[KrisOhn]

Sounds good, doesn't it?

Very. I wish I could consistently get it that fast.

 

[Andy Resnick]

I played around with the panoramic method, the results are pretty interesting.

background- I used two lenses at maximum aperture, a 15/2.8 for the 'truth' image ans an 85/1.4 for the panorama. Here's the 'truth' image:
http://imagizer.imageshack.us/v2/800x600q90/842/ztwa.jpg

I chose this particular composition because it has a clear foreground, midground, and background so I could maximize the effect of focal plane positioning. For comparison, the 15mm has a 9 ft hyperfocal distance while the 85mm has H = 560 ft.

So, even though the center of the image is only 5 feet from the camera, most of the 15mm image is in focus. When I put the 85mm lens on the camera, the focal plane thickness at 5 ft object distance is only 1cm or so (sorry for the mixed units...)

Here's the cool thing- the focal plane on the stitched image will not be a plane, since I have to pivot the camera around to capture the larger field of view. I used Hugin to stitch the 150 images together, using a variety of cartographic projections. Some 'look' better than others, but they all have a nicely curved plane of best focus.

'Rectilinear' projection:
http://imagizer.imageshack.us/v2/800x600q90/203/xzbt.jpg

"Trans Mercator' projection:
http://imagizer.imageshack.us/v2/800x600q90/855/bbmh.png

"Equirectangluar Panini':
http://imagizer.imageshack.us/v2/800x600q90/191/mq2r.png

'Fisheye':
http://imagizer.imageshack.us/v2/800x600q90/835/pkte.png

'Orthographic':
http://imagizer.imageshack.us/v2/800x600q90/689/69ty.png

Lastly, 'Biplane':
http://imagizer.imageshack.us/v2/800x600q90/20/bm40.png

 

[KrisOhn]

Nice! I've noticed that this effect gives a similar effect to what a tilt-shift lens does, but there is something different, I can't quite place my finger on it though. I recommend that you download Microsoft ICE (Image Composite Editor) and combine them into a panorama that way, it's the best image stitcher that I've used and it has very good control over the final geometry.

 

[Andy Resnick]

Alas, ICE is not cross-platform...

 

[danago]

I never noticed this thread previously! I have only just recently gotten into photography. I use just a Sony Nex 6, so nothing too fancy, but for a first camera it is quite nice :) Here is one of my latest shots from Pisa:

http://i42.tinypic.com/1znool5.jpg

 

[lisab]

I didn't take this pic, but it's really interesting and I'd like to talk about what's going on here:

http://boingboing.net/filesroot/299792458mps.jpg

So the kid is blinking. The shutter is going left-right or right-left (depending on if the kid is opening or closing his eyes), "scanning" the field. The reflection part of the photo is taken a slit-second after (or before) the kid part of the photo. Is this correct?

Is there a way to know if the kid is opening or closing his eyes? (Besides knowing how the camera works.)

Do high-end cameras have this "feature", or do they compensate for it somehow?

Has anyone else seen or taken a photo showing this effect?

Edit: my husband just came home, he knows quite a lot about photography (majored in it in college). He immediately called BS. He thinks the photographer took a quick series of shots and photoshopped two of them together.

Thoughts?

 

[Enigman]

May be a rolling shutter:
http://en.wikipedia.org/wiki/Rolling_shutter
(based on a google search of the image)
But I think photoshop based on rainbowing of the ELA in fotoforensics:
http://fotoforensics.com/analysis.php?id=5b23eca8d3c270bd7b1d279a4705254b8471a51f.283427

 

[Andy Resnick]

I didn't take this pic, but it's really interesting and I'd like to talk about what's going on here:

http://boingboing.net/filesroot/299792458mps.jpg

<snip>

Interesting... my vote is a (horizontal) rolling shutter- that is, the exposure was scanned horizontally across the frame. Although, as is evident on boingboing, people have a lot of spare time...

 

[drizzle]

Some pictures from my recent hike.

http://imageshack.com/a/img43/8843/stfq.jpg

http://imageshack.com/a/img593/8709/bqs4.jpg

http://imageshack.com/a/img839/9327/78yh.jpg

 

[Borek]

I like the first one most

 

[drizzle]

I'll try to get pics from higher altitudes next time.

And yes I like it too, somehow observing your surroundings from that angle helps in minimizing life's challenges. :)

 

[sourlemon]

Wow, it's beautiful Gad! They make me feel relax and at peace. Was it difficult to breath?

 

[drizzle]

http://imageshack.com/a/img18/7084/rg52.jpg

http://imageshack.com/a/img27/3585/c0bi.jpg

 

[Enigman]

http://imageshack.com/a/img18/7084/rg52.jpg

​

 

[Borek]

 

[drizzle]

Beautiful Borek. Thanks for sharing. :)

 

[Andy Resnick]

Some pictures from my recent hike. <snip>

<snip>

Y'alls live where it's pretty. jealous = me.

 

[Borek]

400 km from here, so hardly "where I live"

 

[Andy Resnick]

Fireworks in the sky tonight:

And a detail (200%, no interpolation) showing the individual 'bolts' that occur as the spark propagates back and forth:

Details: 85/7.1, ISO 100, 'bulb' shutter setting.

 

[drizzle]

Wow! That is beautiful Andy, good capture. Thanks for sharing. :)

 

[Borek]

Nice ones.

Somehow the last few years we had no photogenic thunderstorm close by (or I was away, or it was during a day, or it was raining too heavily, or whatever).

 

[Andy Resnick]

Rainbow today:

I can't tell for sure, but some of the images (like this one) seem to show the supernumeraries (http://www.atoptics.co.uk/rainbows/supers.htm)

 

[dlgoff]

Dang. I didn't realize how many "flavors" of Rainbows there are.

 

[Beelzebub]

I posted this in the wrong forum a min ago: