Photo Notes

May 31, 2012

More Big Camera Notes

I wrote this for the person who just bought a 8X10 camera from me. I actually know a few people who are working in large format again, so I thought I would post a few notes. I’m going to be shooting people blowing hot glass tomorrow; I’m pretty excited about that. I’m including a few images I made with big cameras.

A photograph is a two dimensional illusion of a three dimensional reality. It has limitations primarily that movement of the viewer’s eye doesn’t change the scene and the amount of detail captured and displayed. The amount of detail can be changed of course, but it is not always as easy as just increasing the size of a capture. There are three primary considerations: depth of field, resolution and capture. Resolution is thought of as sharpness, but the human eye will interpret a contrasty image of lower resolution as sharper than a low contrast image with high resolution. Arthur Cox’s book Photographic Optics shows a good example of this. There are limitations to how much you can adjust sharpness in post-production, but depending on the image, you can increase contrast until there are just two tones: black and white with no intermediate grays.

Lens resolution: Lenses are optimized for different size capture. A lens optimized for a smaller capture has a greater potential resolution then a lens designed for large format work. Fixed focal length lenses have fewer air to glass surfaces, and fewer elements, and so are sharper than zoom lenses. So a 50mm lens designed for a 24mmX36mm (full frame 35mm film area) is sharper than a 150 mm lens designed to be used with 4X5 inch film. The number of air to glass surfaces is not the only indicator of sharpness, and perhaps not the best one. Many lenses with 6 elements are sharper than 4 element lenses, but a zoom with 10 elements that move in different groups is always lower in sharpness than the best fixed focal length lenses. Resolution refers to the ability to separate fine details. A lens that can delineate the details of a feather has high resolution.

Depth of field: Many people interpret this as synonymous with sharpness, but in fact that is wrong. A lens will resolve better somewhere between one and three stops from wide open, then it will at the minimum aperture. Once again resolution is the ability to separate detail. As the lens approaches minimum aperture the diaphragm begins to diffract light, which reduces resolution. So while f64 may keep a lot of stuff in focus it doesn’t produce maximum sharpness. There are computer programs that are able to take several captures and combine them to obtain maximum sharpness and extended depth of field. Also, a larger capture area requires a smaller aperture to obtain the same depth of field.  A 150mm lens on a 4X5 camera is in focus from 32 feet to infinity at f8, a 50mm lens on a 35mm camera is in focus from about 6 feet to infinity at the same aperture.

Capture resolution: This is where a large format camera can make up for it’s other challenges. Film’s actual resolution is a factor of how it is manufactured, so a bigger piece of film has more resolution than a smaller piece of film, just because there is more film. A 35mm frame is 1.5 square inches, while a 4X5 piece of film is 20 square inches, more than 13 times bigger. This relationship is different with digital, more total pixels generally means a higher resolution capture. However I have seen some information that suggests more pixels on a larger capture area can be sharper than the same number of pixels in a smaller area.

As I suggested above you can increase apparent sharpness by increasing contrast, but there are limits. Many times increased contrast just doesn’t look good.

Notes for focus and exposure with large format cameras: Many lenses need to be refocused after you stop them down to the shooting aperture. This can be difficult because the image is so dark on the ground glass. This is particularly true of wide-angle lenses. Also wide-angle lenses are much sharper if focused at the hyper focal distance when stopped down rather than infinity. This means extending the bellows just a little. Put another way: if you have a 65mm lens on a 4X5 camera and you want to focus at infinity with an aperture of f11, you can focus the lens at infinity, but the image will be sharper if you focus at 8 feet from the lens. This is the mid point for your depth of field at that aperture. Total depth of field would be 3 feet to infinity at f11.

Another problem with large format wide-angle lenses is cosign 4 failure. The focal length is approximately the distance from the diaphragm of the lens to the film, when the lens is focused at infinity. As you can figure out for yourself the distance from the diaphragm to the corner of the frame is considerably greater on a wide-angle lens. This means that the light isn’t even across the frame on a wide-angle lens. There are filters that can correct this for you, and I am sure you could also correct for it in Photoshop.

One advantage of a large format camera is that you can selectively focus. This is similar to what you can do with a Lens Baby: shift the plane of the lens so that the focus follows the image or so that focus goes against the image. With large format shooting, where depth of field can be a challenge, this feature is very important.
Thanks for paying attention the blog. I’ll be back soon. Here are the usual reminders.
Please check out my books and classes:

Understanding and Controlling Strobe Lighting: A Guide for Digital Photographers

Photographing Architecture: Lighting, Composition, Postproduction and Marketing Techniques

An Introduction to Photographic Lighting

Portrait Lighting on Location and in the Studio

Getting Started in Commercial Photography

Thanks, John

 

May 23, 2012

Back to the Big Camera

Filed under: Large Format Photography,Marketing — John Siskin @ 7:34 am

I’ve been giving a lot of attention to my new page at facebook: facebook.com/JohnSiskinPhotographer. I’ve added more than a dozen albums filled with images from my article and book projects. I hope you will check out some of this. In addition I have started tweeting; frankly I don’t know how I feel about this pastime yet. So, with all of this, I seem to have neglected the blog. I’m back.

I’ve tried for a while now to get back into shooting 8X10 inch film. I used to really enjoy this. It is extremely challenging, but when you do it just right the results are sublime. I’m not going to attach any images made with the 8X10 camera to this blog, because you might get the idea that a print of a large format image looks like what you see on your screen. It doesn’t, it’s much better. Film is essentially an information storage medium, as is digital. A large piece of film stores information in a more continuous way than a small negative or digital capture. In addition there is a quirkiness to the way large format lenses represent the world. Every current Nikon 50mm f1.8 lens sees in the same way. There were many different large format lenses, and even two of the same brand and design didn’t always see the same way. I mention all this because I recently acquired one of the most marvelous large format lenses ever built: a 14 inch Gold Dot Dagor, built by Kern in Switzerland for Schneider Corporation of America. The lens is the last generation of the famous Dagors, first designed in the 19th century. Let me tell you folks there is a lot of history here and a wealth of fabulous images. Anyway the lens is inspiring me to set up the equipment to develop sheet film. I’m sure I’ll be writing about this in future blog posts.

I’ve added pictures that I made with lenses I assembled. For more about this please check the article I did for view camera. These lenses inspired me to see differently.

One more thing I want to say about the difference between shooting a big camera and a digital camera. When you shoot digital you try to make a good capture and then you have almost infinite opportunity to interpret that capture in post-production. If you shoot film for a traditional print, say a silver gelatin print, you have too make decisions about the final image when you shoot. You can’t, for instance, change the color of the filter you use to make black and white image when you print the image, you can only do it when you shoot. This means you need to think more about the final image when you shoot, not just when you edit. I don’t think this is better or worse, but it is different.

Thanks for paying attention the blog. I’ll be back soon. Here are the usual reminders.
Please check out my books and classes:

Understanding and Controlling Strobe Lighting: A Guide for Digital Photographers

Photographing Architecture: Lighting, Composition, Postproduction and Marketing Techniques

An Introduction to Photographic Lighting

Portrait Lighting on Location and in the Studio

Thanks, John

Getting Started in Commercial Photography

Thanks, John

 

May 3, 2012

Social Media and More

Filed under: Architectural Lighting,Marketing — John Siskin @ 2:19 pm


The images this week are from my book: Photographing Architecture. I hope you’ll check it out. I have included a couple of diagrams so you can see some of the details. Of course my other book: Understanding and Controlling Strobe Lighting: A Guide for Digital Photographers is still available.  I hope you’ll get a copy if you haven’t already.  Of course you know that one reason for this blog is to sell the book and get you to consider a class at BetterPhoto.com:
An Introduction to Photographic Lighting

Portrait Lighting on Location and in the Studio
Getting Started in Commercial Photography

If you’re in the Indianapolis area there are other opportunities as well. I’ll have classes and private lessons at Indy Photo Coach any day. Also I’ll be giving a lighting presentation at the Indy MU Photo Club on June 14. Finally, for now any way, I’ll be teaching a class in commercial photography next spring at Ivy Tech.

I wanted to say a few things about my current marketing projects. I written quite a few times about marketing, but I really haven’t said much about social media. There are several reasons for that, one of the best is I don’t know much about it. My assumption has been that facebook and many of the other sites are very useful for a photographer who shoots families and weddings. I thought that facebook would be of little use to me since my clients are mostly businesses. That may be true, but my business has changed somewhat since I came to Indianapolis. I am still very interested in commercial accounts, but I’m also interested in teaching and book sales. Also since many businesses do market using social media I think it’s important for me to be familiar with this sort of site. So, while I have long had a page on facebook, I now have a page for John Siskin Photographer: www.facebook.com/JohnSiskinPhotographer. It isn’t much yet, but I have high hopes. Also I have taken up tweeting. My handle is @JohnSiskin. I have a coach for social media. He wants me to post a fantastic amount of stuff. I really hope you’ll visit me at these sites: it’s not really social if you aren’t there. I really want your feedback about all these new offerings.


I also wanted to add a few things I said to a student about photographing kitchens. Shooting a kitchen is an assignment in my An Introduction to Photographic Lighting class. Probably the most difficult assignment. I think that people should shoot kitchens as exercise, the way musician do scales. I can’t say it often enough: photographers should practice. The images are mine, I don’t have permission to post student work.


These are good kitchen shots. I’m sure you put considerable effort into these. Kitchens are difficult for several reasons: there are a lot of reflective surfaces, there are windows and there is a wide tonal range. You’ll often see a kitchen with both white and black furnishings, as well as stainless steel and glass. Very often there is no perfect shot, just a best approximation. You have light coming from the umbrella as well as bounce light from the wall behind the umbrella, because you used a shoot through umbrella. One of the few places I use a shoot through umbrella is when shooting a bathroom. When I shoot a bath using this tool the light passes through the umbrella and bounces off the wall behind the umbrella. Since baths are so often painted white this is a good way to get a large light source into a small space.

You have mixed colors of light in both shots from the daylight sources: strobe and window light and the warm sources: the overhead light and the under cabinet lights. In a kitchen shot this isn’t a big problem, people expect a variety of light sources in a kitchen. I think you used a mono-light with the umbrella, but it’s hard to tell in the set-up shots, this would be a daylight balanced light. Often I’ll use a Rosco 1/2 CTO filter over my lights on an interior shot to make them a little warmer than daylight, but not as warm as a light bulb.

The dedicated strobe gave you some problems: the reflection in the windows and the shadows from the overhead fanlight. I think that a bounce light off the ceiling can be very effective in lighting a space, but you need to be concerned about the spread of the light. If you were shooting just a person you could crop out the ceiling, which I’ve done on some occasions. However, most of the time, I need to use a set of barn doors or a snoot over the light to control where the light is on the ceiling. These tools allow me to avoid having my bounce light spread into the shot. You have the shadow of the fan, and the light directly from the strobe, on the tops of the cabinets in one of your shots.
I hope you’ll check out my classes at BetterPhoto. I have been told that prices are going up this year at BetterPhoto, so you might want to sign up soon.

Thanks, John

 

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