Featured

Time on my hands

Since our last project of focus stacking, the next logical question was why you don’t shoot at the smallest aperture to have the greatest depth of field, consequently, not needing multiple captures or even getting by with only one.  Good question, with a one word answer – diffraction. The tradeoff with a small aperture to get the maximum depth of field, apart from slower shutter speed is loss of image quality caused by diffraction.

Diffraction affects the entire frame equally, most noticeable, in the loss of fine detail. In simple layman’s terms, light travels in rays. As it enters and leaves the lens, with a large aperture opening, the rays pass fairly unmolested, with only a small percentage of the rays touching the edges of the aperture, compared to the total amount of light rays, on the journey to the capture plane (sensor or film).  As the aperture is closed down the light rays pass through the smaller opening and a higher percentage are disrupted by the edges of the smaller aperture, this disrupts the path of a higher percentage of light rays and degrades the image at the capture plane. So knowing this begs several questions which I have listed below.

  1. Q – Are the edges of the image more affected than the center?  A– No the entire image circle is uniformly affected.
  2. Q– Is diffraction affected by subject distance to the capture plane?  A– No, it makes no difference if you are shooting at infinity or close up. Lens itself might
  3. Q – So why are lens “offering” an f22 or f32 (in 35mm format)?  A– Well because they can, and with film you can and could stop down further than with digital. And today’s lenses are children of our film lenses. More seriously, depending on what you are shooting, fine detail might need to be sacrificed for depth of field, think clouds, the sea, reportage, small print, or screen reproduction, to name a few examples.  The more you close down your aperture the smaller your best quality maximum final print size will be.
  4. Q– Is the inverse true, a large aperture giving you the sharpest image, most fine detail?  A – The short answer is no. Most lens makers have their own proprietary philosophy on lens design, but it is safe to say that usually about 2 – 3 stops from maximum aperture you are hitting the “sweet spot” for finest detail and “normal” depth of field, depending on the distance to the subject. Should a lens be optimized for sharp detail at maximum opening of the aperture, it surely is advertised that way, that is generally not the norm in common lenses.
  5. Q – Is a five blade aperture more disruptive than an eleven blade aperture?  A – Yes the 5 blade will cause more issues. The five blade aperture will yield a pentagonal aperture with ’corners’. These corners where the blades join cause distortion, when stopped way down, so F16 or F22, can actually produce a star effect.

It should be kept in mind that light rays are bent whenever they hit any object. Also, once diffraction starts to have a negative affect after leaving the “sweet spot”, as the aperture gets smaller, it basically falls off a cliff, the percentage of light getting though the smaller aperture and amount that is being “disrupted” goes up exponentially. There other factors which can mitigate or factor into the amount of diffraction, such as the pixel type and size, film grain size, size of capture plane, which present themselves in the Airy Disc formula, but diffraction cannot be avoided and should always be considered.

So what I did with time on my hands and also curiosity, was test two lenses (a 40mm Rodenstock and Schneider 60XL) on a Cambo technical camera – both stellar lenses.  I used two Phase One IQ4150 backs, the regular color back and the Achromatic. I was looking for the sweet spot on each lens. Also I was curious because one, the Rodenstock, is a retro focus design lens, and the Schneider is a traditional design where the nodal point is close to the middle of the lens. Note also, one back was a normal color back with a hot filter, and color filter of Bayer array design, while the achromatic back had no Bayer array. I was wondering if the Bayer array gets more confused by the scattering of the light, compared to not having one. Also the IQ 4150 is a backlit sensor, meaning the front side which captures the light is less cluttered with circuitry, this is a good thing and a vast improvement over previous Phase One sensors, not just in resolution, but in color cast, and light fall off. It is a fantastic Medium Format back and has the ability to go on a SLR, a technical camera, a studio camera or a field camera.

So anyway these are the results, both back backs were shot at their base iso and on a tripod.

If you are after all the nuances afforded using a fantastic back like the Phase One IQ4150 and these fantastic lenses, with a tech camera, I would definitely tell you to keep your aperture within the range noted in the table.  As noted if you are using any camera where you can adjust the aperture, diffraction is always lurking.

I personally find that thinking about the physics and chemistry behind photography; stimulates the creative side of image making.

RailRoad Tracks

OK this is how it started. I decided to start a six month project to only shoot black and white. So when walking around with the little Leica MM looking for something to photograph, I saw some railroad tracks. Carefully walking along the tracks I found a spot I liked and put the camera on top of the tracks and shot several frames. When I got home I reviewed the shots on the computer and liked the perspective, of the converging lines going off in the low horizon.

I sent the shots out to see what others, people with better photographic knowledge than me, thought and many commented positively in the main, but with one reoccurring point, they didn’t like the out of focus foreground. This didn’t bother me as much as it did others. Cropping was suggested as a fix, but I’m not sure it works here, as the distance perspective is lost, I think.

Anyway;

Sometime later, I came across another set of railroad tracks, and took a couple of shots, this time on one knee, to get the  tracks curving at the vanishing point, which I thought was sorta interesting, conscious to get the foreground more in focus.

On my walk back home I decided to:

  1. Shoot with the Leica MM with a variety of lenses. With the ultra-wide 12mm, then progressively move up to 21mm, 28mm, 35mm, 50mm, and finally with the 75mm.  I would also shoot with a Phase One XT with a 32mm
  2. Focus stack the shots to keep everything sharp using an aperture around f8 on the Leica and F6.3 on the Phase.
  3. Shoot at 3 different heights: on the rail, 18 inches above and four feet high.
  4. Shoot all on tripod with cable release.

Other factors that one would need to be mindful of, that photographing anywhere in Miami in an unshaded area is going to be hot, so need to keep equipment shaded and cool.  Also hydrate!  The other, perhaps more pressing problem, was that these are “live tracks” used daily by South Florida Freight Line, Bright Line Passenger, and Amtrak.  So this is my disclaimer – shooting on “Live Tracks” is not recommended, especially with a heavy bag full of lenses and Tripod and tripod extension.  This could be considered a ‘fool’s errand’, because no way can you get something in focus that is up against the camera!

Anyway, this is what the different heights look like starting from the camera on the tracks (really about 2 inches above, since these were stacked it had to be on a tripod arm). Next, is on a tripod about 18 inches above the railroad track, and finally 4 feet above the track. Remember we are talking about the top of the track, not on the ballast gravel.

Next this was shot with different focal lengths, from a 12mm Voigtlander, through to Leica 21, 28, 35, 50 and also a 75mm. Personally I find myself going wide more often than not. Especially now that we have high megapixel cameras, cropping is a real option. Also the Phase One XT with an achromatic back, and the 32 mm lens which in 35mm format is about a 23mm perspective. Where needed I resized the 32mm to same format as 21mm in 35 mm equivalent.

So what did we learn from all this?  At the very least I became acquainted with focus stacking, using Helicon Focus, and was reacquainted with discipline (in my case, always needed practice).

If I could get permission from higher beings, I would try and go back and shoot with the Cambo and 40mm, which has tilt, but I don’t expect a big change in the framing, as it wouldn’t be possible to use more than one degree of tilt, and even with the possibility of rise and fall there is not going to be a lot of options there.  Maybe using the Arca Swiss field camera and using back and front movements, there could be some improvement, at the least fun and a learning experience. But I would need a couple of things: like Phase One to give us back Capture Pilot, because there is no way I am taking a lap top out on to the track, and oh yes, a train schedule would be very helpful!

Here are three shots I like from the series.

This is a Cropped Infrared shot with the Phase One XT with the achromatic back and the 32mm lens. It is the hook at the vanishing point that is important to me. The Crop gives it the vastness going into infirmity or somewhere close, It is not here.

Straight Stacked Shot from tripod at 4 feet above ground. XT/32mm

Shot with the Leica MM and the 21mm, late in the afternoon I like the 10 or so triangles aiming at the distance.

And the one that started it all

Shot with a Leica MM and a 35mm – Toned

Feel free to comment or ask questions,

Thanks for looking

First Post

As anyone can see, looking at my web site (www.pg-pg.com), there could be a lot of stuff, which is debatable. Anyway, I am going to add a new section, Black and White, While there are quite a few Black and White images there already, the vast majority are converted from color. The new section will contain images shot only with a Phase One Achromatic back and a Leica monochrom. Some off them we can discuss here or in the comments section of pg-pg.com

The difference between converted color and monochome, without getting too technical, is you have much more subtle and smother graduations of tone with a monochrome only sensor. I will still convert when I feel it is appropriate. Color is good; there are so many really good color images out there.

I want to say right now, this is not a zero sum game. While you have a binary choice, B&W or color, and while one genre might tip one way or the other. Images are good, how you arrive there, is not the most important aspect. First you see, and then you feel.

 What appeals to me shooting monochrome, is that you look at things differently, you look for the light. It’s like shooting at night; you are attracted to the light, like a moth. Also I think it’s interesting to set the mood, and timelessness of a B&W image. Much easier to let the mind wander. Like watching an old Hitchcock, The Thin Man, Marx Brothers, Fred Astaire or Orson Wells movie. There is a certain nostalgia and timelessness.  I would assume those of us; of a certain age grew up with B&W TV, B&W magazines, News Reels, and of course our introduction to photography. Also must be said, looking at family photos from our parents.

So without further ado, we are off on a new capture.