Photo Notes

March 28, 2010

Tubes and Bellows

Filed under: Micro Photography — John Siskin @ 7:52 pm

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The further the lens is from the sensor the closer the point of focus is to the lens. I have always thought that this is counterintuitive. If I want to focus closer, and thus make the subject bigger I need to move the lens away from the film or sensor. Regardless of how it should be this is the way it is. So if I could put an empty tube between the lens and the camera body the lens would become a macro lens? Yes, that is exactly right. There are two kids of empty tubes: rigid ones called extension tubes and flexible tubes called bellows.

I think that extension tubes are much easier to work with, particularly in the field. Still you need to do zone focusing, which I discussed in the last blog. A bellows will give you continuous focus. In fact if you start with a long lens, like a 135mm lens, you can focus to infinity with a bellows. Of course this only works with a lens that isn’t in a mount designed for a camera, like an enlarging lens or even a view camera lens. But you can use a standard camera lens, like a 50 f1.8 with an extension tube or a bellows. Fixed focal length lenses, particularly shorter focal lengths work very well with either the bellows or the tubes.

Nikon has made a lot of both tubes and bellows over the years. The first tubes I know about were the K tubes. These were completely manual. Not only didn’t they give the camera any auto-focus information or exposure information, they didn’t even stop the lens down automatically. When you see a set of these they’ll generally be pretty cheap. There are also a lot of other brand tubes that are very inexpensive. Since there are no actual optics in an extension tube buying cheap may make sense.

Spring Flower 1There is one tube that I should mention the Nikon BR-4. This tube will stop down a lens before you shot if you use a dual cable release. So you can use this with manual tubes like the K tubes, or with a bellows, because bellows don’t stop the lens down either. You can also use it if you reverse mount a lens, which I’ll get to soon.

I really like having a few extension tubes in the camera case. They don’t take up much room and they provide a really high quality macro image. I’ve attached a bunch of images made with extension tubes. One other thing I want to mention about bellows: you can adapt a view camera to a digital camera and use the bellows of the view camera. This gives you camera movements in addition to simple bellows. You can read more about his here.  Next time, more macro!

I have a new article on Architectural Lighting coming out in the May/June issue of Photo Technique Magazine . I hope you’ll check it out. I also hope you’ll check out my classes at BetterPhoto.

An Introduction to Photographic Lighting

Portrait Lighting on Location and in the Studio

Business to Business: Commercial Photography

Thanks, John Siskin

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March 24, 2010

Getting close, a Beginning

Filed under: Micro Photography — John Siskin @ 10:50 pm


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Micro and macro lenses adapters tubes bellows copy stand and a ring light.

In the spring a photographers’ thoughts turn to macro and micro photography. At the same time the photographer’s wallet turns inside out. I know that most people feel that the way to do micro photography is by buying a micro lens or using a macro zoom. Micro lenses are very fine, but a 60mm f2.8 Nikkor costs $600, and the micro 200mm is about $1800. I think this is a lot of money. Many micro zooms are just not all that good optically. The other problem with much of this gear is that it doesn’t get you all that close. I’m going to do a few blogs about unusual micro equipment. I might finish off with something about microscopes. I’ll start with some general things and the work into specific set-ups. One thing, I know that almost no one will actually want to use most of these set-ups. They require manual control and some thought and some experimentation. You will not always take good pictures. The trade off is that you can go MUCH closer that you could with a standard macro lens. Macro lenses tend to stop at the point where the subject is the same size on the sensor that it is in life. A microscope will allow you to make the subject eighty times larger on the sensor than it is in life. That is eighty times closer than a macro lens.

I will be discussing the adapters for Nikon lens mounts. There are adapters for other systems. Since I don’t think most people will actually be assembling these things, I’m not going to bother to find out what the adapters are for other systems.

Macro and micro are terms that get used interchangeably. Nikon calls all their close up lenses micro, Canon calls them macro. I am going to call close-up images that are less than life size on the sensor macro. Images that are more than life size on the sensor will be called micro. If you want to call them something else that is ok by me.

I used a +3 diopter

Some set-ups allow continuous focus; others only allow zone focus. This is important. Zone focus means that the lens will only focus over a limited distance, or that it is fixed focus. I like zone focus better. You set the system up and then weave back and forth till you find the right image and focus. Then you shoot. This is actually easier than racking the focus back and forth.

Lighting is important also. For most of the shots in the next few blogs I used a Sunpak 611 with a booty light cover. (http://siskinphoto.com/blog/?p=189) This gives a large light source since the object is never more than a few inches away. I like the Sunpak because it has manual output over a long range, down to 1/128 power. Any strobe with manual control will work well for micro work. You can use a ring light, but this has problems when you are really close. So I like the Sunpak. But I have a ring light. I am including a picture of all the micro items I’ve acquired. If you click on the image you’ll get a larger image.

Now that I’ve introduced everything I’m going to finish up with something simple: diopter lenses. These are basically reading glasses for your camera. They screw on the front of the lens like any filter. All auto features remain automatic. They are inexpensive (a set of 3 in 52mm is about $50). They are not always all that sharp. Still they’re good to have in the camera bag. You can also make large format lenses out of these filters, check out this article.

I used the +3 diopter

Next week extension tubes!

I have a new article on Architectural Lighting coming out in the May/June issue of Photo Technique Magazine . I hope you’ll check it out. I also hope you’ll check out my classes at BetterPhoto.
An Introduction to Photographic Lighting

Portrait Lighting on Location and in the Studio
Business to Business: Commercial Photography

Thanks, John Siskin

Once again the +3 diopter


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March 14, 2010

Large Light Sources

Filed under: Lighting Technique — John Siskin @ 11:23 am


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This image was made with a snoot, so the light source is very small.

People are often confused by the difference between what happens when you use a diffuser and when you use a device to make a light source larger. The language of lighting doesn’t make a good separation between these ways of modifying light. A regular reflector on a strobe or even a clamp light acts to keep light in one direction. Various reflectors modify the spread of the light, so they are known by the degrees they cover: a 30º reflector throws a tighter beam than a 60º reflector. A diffuser takes the light from a reflector, or from the built in reflector in a strobe light like an SB900, and spreads it to cover a larger area, generally everything in front of the light, say 180º. This is what the booty light does. A large light source does do this, but it does something else that is more important. Whatever light source you use, each point on the light source, whether it is 12 inches across or 12 feet across, lights each and every point on the subject, unless that point is shadowed by something between the light and the subject. So if you have a face the nose will throw a shadow with a small light source since the nose will block all of the light coming from the small light source. If you have a large light source the nose will block some of the light source, but not all of it, because there will be part of the larger light source that isn’t blocked by the nose.  So

Made with a translucent cloth over a light pane to give the light a hard/soft quality

you get softer gradation, because only some of the light is blocked by anything between the subject and the light, and you have reduced, or no, shadowing. How soft the light is depends on the size of the light source. Other factors include the distance from the subject to the light source and how translucent the fabric in the large light source is. A very translucent fabric creates both a hard and softened effect, because you can see the effect of the small light source in the larger light source. In the same way a silver fabric doesn’t spread light in an umbrella as much as a white satin fabric. The basic tools to make large light sources are umbrellas, soft boxes and light panels. The key is the size of the source more than the shape. So a 60-inch umbrella and a 4X5 foot soft box will make very similar light, and a 1X1.5-foot soft box will give a very different quality of light. In my classes I stress using large light sources, because of the quality of light they create. For more information you might want to check out this article.

I have a new article on Architectural Lighting coming out in the May/June issue of Photo Technique Magazine . I hope you’ll check it out. I also hope you’ll check out my classes at BetterPhoto.
An Introduction to Photographic Lighting

This image was made with both hard and soft light sources.

Portrait Lighting on Location and in the Studio
Business to Business: Commercial Photography

Thanks, John Siskin

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