PF Photography: Tips, Tricks, & Photo Sharing

[dlgoff]

On Saturday I went biking - and saw these people:

Nothing extraordinary, but berkeman was on the EMT shift during SWAT competition, or he was training as a part of this competition, or he was doing both at the same time - so it was hard to not think about him

Very cool photos. I can just visualize berkeman there. He'd probably have a hand-held radio in his hand.

 

[Andy Resnick]

Check it out- a microscope that looks sideways:

http://imageshack.us/a/img845/5889/jqzo.jpg

Last week I happened to see this odd item offered on ebay:

http://imageshack.us/a/img46/153/73ci.jpg

It's not clear what this is- the left is an undersized (for Zeiss) ring dovetail and the triangle on the right is a prism housing. The slider adjusts an internal diaphragm, so the numbers most likely correspond to an f-stop.

 

[Borek]

The slider adjusts an internal diaphragm, so the numbers most likely correspond to an f-stop.

22 32 45 64 are even part of a standard series, so it would be my idea as well.

 

[ABD EL HAMEED]

Pics of school

 

[Andy Resnick]

4 ZapperZ: thanks for the hints and tips!

http://imageshack.us/a/img34/5444/5irq.jpg

 

[Borek]

Fireworkageddon:

 

[KrisOhn]

I was just reminiscing about my early days of photography and thought I would share a comparison I was looking at, my first astrophoto, to my most recent.

http://i.imgur.com/cfw2FHP.jpg
http://www.flickr.com/photos/krisohnander/11678558446/

It's amazing what 3 years can do.

 

[drizzle]

Nice photos Kris! I enjoyed the whole album. :D

And you're right, such improvement.. Which gives me hope that I'll master it one day.

 

[lisab]

I was just reminiscing about my early days of photography and thought I would share a comparison I was looking at, my first astrophoto, to my most recent.

http://i.imgur.com/cfw2FHP.jpg
http://www.flickr.com/photos/krisohnander/11678558446/

It's amazing what 3 years can do.

That's fantastic .

 

[KrisOhn]

Nice photos Kris! I enjoyed the whole album. :D

And you're right, such improvement.. Which gives me hope that I'll master it one day.

Thank you! It happens so slowly that you don't really notice it until you have a sudden urge to look back. Making small improvements every day goes a long way over the time of a few years.

That's fantastic .

Thanks!

 

[KrisOhn]

I tried my hand at something called the Brenizer Method today, for the first time. Its when you use panoramic stitching and a long focal length lens to create a wide angle shot with a shallow depth of field. It took me 3 hours, several hundred shots, and more frustration than necessary to get this shot, and even then, I can see lots of imperfections with it. Very cool end result when it does work though and that is enough to keep me motivated to experiment more with these. I shot this with a 50mm prime f/1.8 lens, which I think is probably the shortest focal length you can use to make a Brenizer easily, I would really prefer to be shooting at 150mm+ but I don't have that kind of glass. Still cool though.

 

[drizzle]

Such a rich picture, Kris. I like it.

 

[Andy Resnick]

I tried my hand at something called the Brenizer Method today, for the first time. <snip>

Interesting... thanks for the info!

 

[KrisOhn]

Interesting... thanks for the info!

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

Here's another shot using the Brenizer Method, this one came together a lot better than the last one, but I think the background is a little too busy and distracting.

Here is a higher resolution version.

 

[KrisOhn]

Played around with an old, old flash and the bathroom sink today. I noticed in shots where the water was less stationary than this one that even though I was using strobist techniques, in a dark room with a flash, to get extremely fast apparent shutter speeds, there was still motion blur. I think this must be from how old my flash is and maybe how low the batteries were on charge. I would really like to get a newer flash that could be synced with my camera, but they can easily run $500 or more, so I'll stick with this for now.

 

[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...