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Wednesday, January 7, 2015

Field test: Pentax DA 300MM F4

I'm on vacation on the West Coast of Florida this week and I have had more time with the camera than any time since I bought it. I normally don't use long lenses but I had a chance to pick up the Pentax DA 300 used at a fair price so I thought I would bring it along. It was a good move. 

We are staying in a 9th floor apartment overlooking the Gulf of Mexico in Longboat Key. I've got sort of an homage to Hitchcock's Rear Window going by taking shots from the balcony. Unlike Jimmy Stewart I am not in a full leg cast and wheelchair, sadly Grace Kelly is not by my side either, but I digress.

Years ago someone came up with a formula that the minimum shutter speed should be 1.5 to 2X the focal length of the lens. In other words, shooting with a 100MM required a 1/150 to 1/200 sec shutter speed.  It was widely adopted however, if you made your print large enough you would find that there was always a bit of motion blur to speeds 4 or 5X the focal length. For practical purposes the formula worked well.  It dawned on me a few weeks ago that with APS-C the working focal length is half again the physical focal length, so the 300MM requires 1/450 to 1/600 second as a base shutter speed for hand held shooting. I found that for me that was inadequate so I start at 1/750 if I am not using a tripod. So far I am quite impressed with the sharpness of the 300MM.

People gathering for sunset at water's edge. 300MM, 1/750 @ F4
300MM, 1/750 @ 5.6
Fisherman pulling in net, 300MM, 1/750 @ 9.5
I've read some reviews with complaints about the AF speed on the 300. This is a lens that focuses as close as about four feet. If you are going from four feet to infinity it may seem to move along slowly but I find that after the first focus is set, more reasonable incremental adjustments are quick. 

Color and contrast on the lens fit the bill for me, I haven't noticed any serious CA at all. Fit, finish and the design of the lens are superb. Weight is substantial at about 37 ounces and the lens is a tad over 7" long and with internal focus does not extend. It is easy to hand hold and the balance of the lens on the K-3 is just right. I like the tripod collar configuration with the removable foot in particular. Removing the foot makes the lens a bit thinner allowing it to slide the lens in and out of my camera bag easily. The only thing I do not like about the lens is the removable lens shade. This is a large lens on a K-3 body and it is not exactly unobtrusive. The lens shade adds about 4" to the length and makes it look like a potato launcher. Is it really necessary to have a large PENTAX logo on the shade? A built-in retractable shade would make this lens near perfect. 

Recommended 90 points

Saturday, December 27, 2014

Schneider PC TS Makro-Symmar 90mm f/4.5 Lens

Before I write up the Schneider lens, I would like offer a little history of PC lenses for 35MM. In 1962 Nikon introduced its first perspective correcting lens, the 35MM f3.5 PC-Nikkor. For users of fixed back 35MM cameras, this was a breakthrough, offering an important feature of view cameras, the ability to shift the composition, repositioning foreground for example without tilting the camera skyward. The second breakthrough came thirteen years later in  the Nikon 28MM F4 PC. With a wider perspective it was more useful for architectural and interior photographs.

Fast forward to the 21st century to a myriad of lenses available from major manufacturers plus a few from lesser known contenders, e.g. Hartblei, Samyang and more. Most of today's perspective correcting lenses also offer tilt control. This enables the photographer to increase or decrease the depth of field using the Schleimpflug principle. Generally speaking that means with the camera back parallel to the subject, a downward tilt of the lenses increases the depth of field while an upward tilt shortens it.

There are alternatives to 35MM of course, technical cameras like the Arca-Swiss and Cambo. They are more precise, can tilt and shift with greater degrees with any lens and use larger format digital backs.  They offer the ultimate image, but they are slow working, cumbersome, not general purpose oriented and considerably more expensive. The middle of the Arca-Swiss line, the RMD3i starts at $5,500 for the box, no digital back or lens. That said, if I had enough work to justify the purchase, I would buy one. Now, back to the real world.

I have switched back and forth between Nikon and Canon lenses over the years. I go for the brand with the best glass. When Canon introduced the 2nd generation 24MM TS-E II, they raised the bar for perspective correcting lenses. They also offer the widest of the perspective correcting lenses, the Canon L 17MM TS-E, a fabulous lens.  Lately I found myself wanting a longer tilt shift lens. Canon still offers the 90MM TS-E, but it is an old design for film cameras and due to its small image circle and none-rotating mount, has a middling reputation. The issue for most of these lenses is the fall off in resolution as one approached the limits of the shift in particular. I am not a techie, but I understand this has to do with the image circle that covers the sensor. The Canon 90MM TS-E offers a 58MM image circle while the newer Canon 17 and 24mm lenses offer a 67MM image circle. The Schneider 72MM image circle makes it best in class.

Let me take the comparison a bit further. The $1,400 the 90MM Canon TS-E 2.8 lens is compact, light weight lens at  3 X 3.5", 1 1/4 pounds. The Schneider PC TS 90MM is about 4.25 X 5.5 inches, not compact at all and weighs in at almost 2 1/2 pounds. It is also more than double the price of the Canon at $3,180. The Schneider, available in several mounts, is a fully manual, unchipped lens. It does not communicate with the camera. There is no automatic diaphragm, so light measuring has to be done stopped down. While not as slow to work with as a technical camera, it is a bear if you like the speed and efficiency of the Canon or Nikon lenses. All this doesn't sound like an attractive alternative until you see the images. The  German made Schneider PC TS Makro-Symmar 90MM 4.5 lens is in a class by itself.

The following photos show you the difference between shooting with no corrections, with shift correction only and with both shift and tilt correction. This was a quick set-up I did on my dining room table. Window light was coming from the back and left and a small LED light was used with a diffusion panel for the right foreground. I was using the Schneider 90MM on a Canon 5D III.

The first three images were shot at 4.5, 8 and 16. Notice the changes in the depth of field. Prime point of focus was the front label. You will notice that the bottle of Don Julio is quite readable at F16. The foreground however is cropped. If I tip the lens downward I can include the entire bottle, but I will change the shape of it through perspective distortion.

F 4.5

The following three images were made with shift correction to bring in the foreground without changing the shape of the bottles. It is important here to make sure the camera back is perpendicular to the set. 

As you can see, using the shift enabled me to include more foreground without distorting the shape of the bottles. I reversed the aperture settings going from F16-11-4.5. You can see the incremental changes to the depth of focus. The front label was the point of focus. 



In this last shot I used both the shift and tilt, using the Schleimpflug principle to increase the depth of focus.  Note: This is not the position the lens was in for the shot below.

 At F16 there is a range of sharpness from front to back and top to bottom that I find very pleasing.  Compare the first shift shot @ F16 and you will see a big difference in using the tilt correction with the shift. 

Tell me more, you say? OK. If you work with the newer Canon TS-E lenses you will notice that they have what is called a super-rotator feature, the ability to fully rotate the lens within the mount. 

What this means is you can juxtapose the tilt and shift in any combination of axis. If I recall, the Nikon 24MM PC-E will only tilt in the horizontal plane. Some folks have either modified the lens themselves ("do not do this at home") or sent it to a shop to have it modified to the vertical position. The Schneider 90MM offers the ability to do the same thing as the Canon but with a different mechanical approach. For me a big advantage over the Canon lens is that the controls are large ring dials, easier to grasp than the tiny knobs of the Canon TS-E. The mechanism of the Schneider also seems smoother and more robust than the Canon. A couple of other pluses for the Schneider. The lens comes with a tripod collar that is Arca-Swiss compatible, I love that. The included padded case has a flat back end that makes it easy to safely position the lens within it. Most importantly, even though this is a maximum 4.5 aperture I found the view through the lens quite bright. I don't know if that has anything to do with the image circle but I could focus it well by eye and then confirm with live-view. 

All of that said, the Canon 90MM TS-E is a good lower cost alternative if you are an occasional user and do not need the full rotator function. You'll also enjoy full integration with the Canon electronics for full AE function if you prefer. The Canon can also be used handheld as a regular 90MM 2.8, albeit with manual focus. This is not something I would try with the bigger and slower Schneider. There has been talk for a couple of years of a new Canon 90ish MM TS-E (II) lens but so far it isn't anywhere on the horizon. If it does come out, I would guess the price to be in the $1800-2100 range, still less than the Schneider by about a third. 

This wraps up my first impression of the Schneider. If my feelings stay as strong for it I may look into the 50MM 2.8 PC TS. There is also a new Schneider PC TS 28MM 4.5 but it books out at $8300.00, more than double the other two lenses in the series. Yikes. 

Recommended  95 points

Tuesday, November 25, 2014

Show 'em what you do

I'm taking a little break from gear reviews today to offer up something I think is particularly useful, especially for those of us who shoot for a living.  Many of you are aware that my assignment work is about 75% architectural. The nature of shooting structures and interiors is that it is more technical than some other kinds of photography. Interior photographs, which can include several different lighting sources and great range of dark to light areas can be the most difficult. Even when supplementing lighting I have used as many as 27 exposures to cover a five f-stop range to gradually build from readable shadows to lights that do not burn up in the image. This composite process requires a lot of time of course, but it is hard to explain to a client. Let's face it, do you need to know how sausage is made? 

Exterior elevations have different challenges. Bracketing is at most 3 f-stops and layers are usually limited to 3 or 4. It is the retouching that is the challenge. A few weeks ago I got an assignment to photograph a couple of buildings for a property offering. These buildings are in an area of Maryland that is known for R&D and bio science firms. Typically, they are two-story, low, long buildings. The nature of what goes on inside them is secret, so their ambiance is that of the Manhattan Project, but with grass and paved roads.

The nature of this beast is that, unlike interiors, there is no way to shoot at ground level and totally avoid visual obstructions, e.g. signage, stop lights, ugly cars in the parking lot, mechanical boxes etc., and of course there is the vehicle flow on adjacent roads to deal with. Shooting on weekends yields an empty parking lot and traffic is lighter. Carefully timing the bracketed exposures between stop light changes gets enough frames without cars but what about all of that other stuff? This is where top notch retouching skills are a major asset. Fortunately, I work with an assistant who has the requisite skills to deal with almost any issue. How far we can go depends on the client's needs and budget.

The before and after shot below is a good example of taking a visually cluttered shot and cleaning it up. The problem areas are marked in orange so you can see the work that was done to create the finished image. Keep in mind that whenever something is removed a hole is left behind. Sometimes a little cloning fills the bill, other times, 3-D modeling is required. The client complained about the dormant trees and had to be reminded that we were shooting in November, but we added a little life to the photo by leafing the trees in the background along the walkway. There is a light pole on the right side of the image with one of the two original traffic lights that I would have liked removed, but the amount of time and cost to do so would have pushed the budget too far. 

Normally I would not show a client workflow, but there was so much involved in this shot I thought it a good idea to present it with with notations. She sent me an email thanking me for it, she said her team now had a better understanding of what is involved in producing the photos. For me, that meant that my work is better appreciated and my fees validated. That, dear friends, is a wonderful thing.