Lens Spotlight: M400 - Jason Doss

Lens Spotlight

smc Pentax-M 400mm f/5.6

& Converter-A 1.4x-L

The Pentax SMC-M 400mm f/5.6 is the second longest, second largest lens in my collection.  By comparative standards, there is nothing particularly striking that separates this lens from other 400mm lenses from the time period.  It weighs in at 1240g (2.7#) and is 277mm long (10.9in), and bears 77mm filter threads, a fairly standard size nowadays.  The lens has a built-in sliding lens hood with a thumbscrew that, if positioned correctly, does double-duty as a gun sight.  Very handy indeed!

The lens has a built-in tripod mount, something missing from some of Pentax's shorter telephotos like the M*300 and the K200/2.5.  Two hands are required at all times, one on the camera, and one on the lens focus ring.

In my collection, I work thru lenses in a random order, and I treat the addition of teleconverters as a separate lens. So, this time, the M400 Macro is paired with the 1.4x Pentax teleconverter of the day, which was the Converter A 1.4x-L. The teleconverter adds 1.1 inches and 6.2 ounces to the package. The fit is tight and comfortable. The combination behaves as a 560mm f/8 lens very good image quality.

This converter is noteworthy due to the protrusion of the front element assembly into the inside of the host lens.  Because of this construction, the list of compatible lenses is fairly short, and careful examination will show that the M400/5.6 is not on that list.

Upon inspection of the lens, it turned out that the only thing preventing entry of the converter front element assembly was a metal o-ring with thin baffles on the side.  So, I located a 3-D printing service, handed over the o-ring with requests to duplicate it minus the baffles, and ended up with a round O-shaped o-ring (as opposed to the original which was squared off in the middle).  The plastic was flimsy and it took some fiddling to get it in, but in it got... and the 1.4-L converter slipped into the lens like it was made for it.

In other words, if you have both the M400 and the 14-L, don't try to fit them together without modifying the lens first.

Kawai scavenges the infrared ditch<br />
K-1 mII, M400f5.6 & 1.4x-L, digital infrared effect done in processing

I've only got two for you this time.  On this day, the boys and I had a walkabout with this lens setup, a tripod, and a desire to create some photos for this blog.  I came away with only two, unfortunately, and I'll tell you why.  First, though, the shot above is a B/W shot of Kawai investigating the ditch, where he often finds curious critters including a snake.  I converted the image to a digital infrared because the look of the white leaves (instead of green) look cool.

The bottom photo is a pot of mums recently picked up to celebrate the fall.  In this case, I shot two photos, one with the normal shutter, and one with electronic first curtain shutter.  Both shots were done on a tripod, and with a 12 second delay to minimize vibration.  The shot below is the one with the electronic shutter.  I suppose my tripod sucks... well, I know it's not a heavy duty tripod and it does take some time for vibrations to dampen down.  However, the shutter slap inside the camera (when the mirror flips up just before exposure) created a significant amount of blur in that image (not shown).  This one looks plenty sharp and clear to me.

Mum's the word<br />
K-1 mII, M400f5.6 & 1.4x-L

That's all I have for now... See you next time.

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