Bokeh

Good evening,

Today we are going to get into bokeh. I probably should have done this one before the shaped bokeh one.

Bokeh is a dramatic sci-fi movie that did not get good reviews (sorry it popped up while searching for the actual definition). Bokeh comes from the Japanese word boke which has multiple meanings such as stupid, unaware, or clueless. It can also mean funny man in a double act comedy. As for photography though it is used in regards to the out of focus area in a photograph. It shows up as bokeh with an "H" to show that it is pronounced bok-ay. 

It is a lens trait and not the camera. Some lenses produce a nice smooth looking blurred area others not so much. The effect can be seen in movies too, just keep an eye out during dramatic scenes with a limited area of focus. The lights in the background will be a blur but have a shape, octagon, heptagon, hexagon, pentagon, and every once in a while a circle. In a movie it is not as noticeable because of the moving images. Pictures though can be studied and savored so more focus can be placed on it.

Below is a series of pictures of a wind spinner with yellow flowers in the background. Going through them we can see that they come into focus but also loose that nice round blurry shape.

Lenses and aperture are the creator of bokeh. Wide aperture (f1.8 or less) lenses are more common to have good bokeh. However it depend on the aperture blades too, the number and whether they are curved or not. 

Here is my 50mm f1.7 Minolta lens aperture. It is open about 1/3 or maybe 1/2 of the way. I am using it to show the blades and how bokeh changes through the range. 7 blade which appear to have a curve.

Here we have lenses wide open and back lit with a white translucent cap on them. First is a a Minolta 50mm at f1.7 notice how it looks like a perfect circle. Next is a 70-210 (Beercan) at f4 it still looks round there are a couple of dark spots around the edges which I believe are the corners of the aperture obscuring the light it still has good bokeh. Last is the 75-300 at f5.6 and the 9 aperture blade edges are obvious depending on the subject this could have a visible effect, for most things it would probably be fine. These photos of the aperture were a little rushed, just wanted to get this out today.

So grab a large aperture lens then go out and shoot.

~Scott

Lenses: Focal Lengths

Good Morning,

Today we are going to talk about focal lengths and their effects on images. We have discussed different focal lengths and what they are generally used for. We have not talked about how they affect the image or rather the relationship between subject and background. Below is a series of a red rose with a praying mantis on it in my backyard. I tried to stay focused on the same spot of the rose but moving and changing lenses does not help, thankfully the wind didn't give me any issues. First image is at 11mm, some distortion can be seen on the wall and the area of focus is wide and it looks like the wall is pretty far away. The second is at 18mm and the wall looks closer, pretty much everything looks closer or tighter, the distortion at the wall is negligible, and praying mantis is still judging us. Third we have 50mm and we can barely see any of the wall, the image is a bit brighter, I didn't have it on manual and it changed shutter speed was changed in Av. The honeysuckle doesn't look as far as it did before and out area of focus seems to have shrunk.  Fourth is 100mm and it was switched to manual mode. The praying mantis is so judgemental and has been for a while. It appears that the honeysuckle is just behind the rose bushes leaves and is rather out of focus. Fifth and final image is at 300mm, sorry the angle changed a little to keep in the same size I had to go up a step. The mantis stared directly at the camera, finally. The leaves are hard to make out on the honeysuckle now and look pretty close.

As can be seen through the images. If a subject is kept the same size the relationship with the background can be greatly affected by the focal length of the lens. What we are trying to convey with our images can be changed by zooming. Now go out and shoot.

~Scott

Equipment: Specialty Lenses

Good Afternoon,

I am planning on changing the posting day to Tuesdays. Sunday just seems rushed. I meant to post this last Tuesday my life has been a little hectic. Next post day should be the 14th unless tomorrow goes amazingly well then I will have a post on 7th.

Last time we talked about regular lenses. Now we will go over specialty lenses. There are quite a few Lensbaby has a whole line, and there are tilt shifts as well. The ones that I have had experience with as of now are Macro, Pinhole, and Fisheye. I don't have a fisheye at the moment but I have used then before and am not a fan.

Macro lenses project the image onto the film or sensor at a 1 to 1 ratio or larger. This means that the image on the sensor is the same size as the subject. With a Sony crop sensor (23.5 x 15.6mm) an image of a dime (17.91mm) would not completely fit on the sensor. There are lenses that have a greater than 1 to 1 ration, there are close up filters, and there is also the technique of reverse mounting a lens. I haven't had a chance to experiment with a greater than 1 to 1 lens, Canon MP-E65 is the only one I can even think of (1x to 5x magnification). There are also some zoom lenses out there that say Macro on them and get you a 1 to 2 or 1 to 4 life size, they are not true macro but they are a step if you want to try it out.

I have tried close up filters when I got my first DSLR (a Canon XTi) and didn't have much luck with them. It goes back to the quality of the glass that you put in front of your lens the ones I had were cheap and came with the camera from an aftermarket seller. Update: I found an old close up +3 filter and tried it on my 75-300mm Minolta. First image is without the filter at 75mm, the second image is with the filter at 75mm. All I did was move the tape measure roughly 3 ft closer to the camera.

Reverse mounting lenses I have tried with minimal success, I might not have given it enough of a chance. It was a dual threaded empty filter ring and the front elements of the lenses were front to front, focusing was done by moving the camera back and forth. There was very limited control and the depth of field was razor thin. If I recall correctly I had part of an insects eye in focus and part out of focus. I will look for some of the results from using it and post them here.

Pinhole lenses, lens is a little misleading, are a small hole that allows light into the camera. Most lenses have a range of f22 to f32 for the f-stop. Each whole stop, DSLRs can generally to 1/2 and 1/3 stops, halves or doubles the size of the aperture depending on if we are making in smaller or bigger. The pinhole in the picture above is around f190 and it roughly equates to a 50mm lens. The clear image above is a 50mm at f7.1 and the not so clear image is about 50mm and f190. If we are serious about pinhole photography then we can alter the thickness of the foil to obtain a more clear picture. I have found interesting images when searching with the parameters of “pinhole” “sun” and “long exposure.” In this case diffraction is the cause of the blurriness and this is the reason that we should probably stick to an aperture around f9 while using a lens. Going from f22 or f32 to f190 is about 6 stops (1.5% of the light) and about 5 stops (3% of the light) respectively. If we have a scene where detail isn't as important as the play of color and light vs dark then a pinhole is great. There are products we could buy for this type of photography or we could make one ourselves. All that is needed is a spare camera cover, a drill, foil, tape, and a needle. I used and insulin needle which I believe was a 31g. Pictures 3 and 4 in this slide show above show my finished result. Personally it is fun to play around with but I have yet to produce a worth while picture with it. That is all I have so go out and shoot.

~Scott

Equipment: Lenses

Good Evening,

We haven't really talked about primary equipment. It probably should have been done before filters. Let's start with lenses. The camera lens focuses light onto the sensor through an assortment of different shaped lenses inside of it. The eye changes focus by changing the shape of the lens with small muscles and this is how we have such a wide range of focus, from around 6 inches in front of our eyes to infinity. Glass lenses can't, at this time, change shape like that so they change the distance between the pieces of glass for a similar effect. The aperture takes the place of the pupil, opening and closing to let more or less light in as the situation demands. The aperture affects the image as well with things such as bokeh and starbursts.

There are many types of lenses which can be broken down pretty far. I am trying something new with the blog, carousels. Click on the pictures to cycle though the images.

Below is the same shot of the moon at 11mm, 18mm, and 35mm.

Wide angle - used for landscapes, cityscapes, and interiors (this would also include ultra wide lenses). Depending on the person this is anything less than 35mm in crop sensor and 50mm in full frame there is wiggle room in those numbers though. There is a wide angle of view on these lenses, not as wide as the human eye though which is about 180 degrees if you have both eyes functioning. For example an 11mm lens on a crop sensor has 104 degree angle of view, a 35mm has 42 degree, and a 50mm has 32 degree.

Below is the moon at 50mm and 70mm.

Normal angle - used for portraits, general shooting. This focal length is more or less how the eye sees the world. If we open both eyes while looking though the view finder each eye will see everything about the same size. For full frame I always heard 50mm and I have heard the same for crop sensors too which doesn't make sense. I just picked up a full frame (FF) and crop sensor (crop) camera and found it to be around 50mm for the crop and 70mm or so for the FF. More or less anything between wide and telephoto.

Below is at 100mm and 300mm which is about a typical or so range for a telephoto zoom.

Telephoto lens - used for sports, wildlife, celestial events, aviation. This type of lens brings everything in close. On the lower focal end they have use in portrait photography and macro photography. The price that we pay to get far away object closer is we loose wide angle of view. As an example a 75-300mm lens has field of view range of 21 - 5 degrees on a crop. If we want a close up of a bird or the moon then we don't need those extra degrees though.

Then there are zooms and fixed. Fixed lenses can often have wider aperture, can cost less, and can be sharper. We have to have many of them though or decide to "zoom" with our feet. Zoom lenses cover many focal lengths, the downside is that they are usually more expensive, they might have apertures that aren't as wide, and less expensive ones might not be as sharp. We come to a point where we make a decision of one over the other and deal with the downsides. I have both zooms and fixed and take which ones I need on each outing that I feel will be suit me. Now lenses don't only have to fit into these boxes. A telephoto lens can be used for landscapes and a wide angle can be used for sports and celestial events. Be creative and see what works for each situation.

I feel that lenses are worth more of an investment than the camera. I have multiple lenses that are still functioning fine that were discontinued in the mid 80s. It was all film back then. If a lens is taken care of it will last longer than the camera it came with. We can get into specialty lenses at a later date. Now go out and shoot.