Pentax FA*600 and Pentax A*400 and Pentax FA*300 f/2.8

DA*16-50 @50mm
The above photo is not part of the analysis here. It's taken at 50mm and shows the Orange excavator dead center. This is to help keep things in perspective. There is some brush in the foreground, and depending on the lens some interferes with the pictures and in some cases it doesn't. That is life, we don't always have 'clear shots'.

Pentax FA*600 f/4 results

Click photos to enlarge
FA600 + 0
There are 3 different versions of each photo in the test series available. The thumbnail which you are looking at, and behind it is a screensize (1200pixel wide) reduced image (typically 160k). Since you may want to look at the full meal deal, the Link shown loads a 1.2m photo. Depending on your browser it will either size itself to the screen and allow you to click it to full size (with scroll bars) or it will load at full size with scroll bars to see the rest of it. In the large size it will be full frame of what came out of the camera. The photos were taken 'Raw', and in the course of developing them, I attempted to equalize the exposure overall, and I toned down the highlights and added some midtone contrast to attempt to make the lettering on the Orange excavator as readable as possible. All photos were taken on a high quality tripod with a gimbal head, using mirror lockup and a remote release. The first photo of each lens sequence was taken without a converter.
FA600 + 0
This is a retake on another day with some better light---F8 @ 1/500 instead of F4 with the Pentax FA*600 f/4. Ground fog had not quite lifted. Note heavy due on machine.
FA600 + Pentax 1.4x-L
Above with Pentax 1.4x-L converter
FA600 + Pentax 2x-L converter
Above with Pentax 2x-L converter
FA600 + stacked converters
Above with Pentax 2x-L converter stacked with the AF 1.7 adapter (converter). Even with mirror lock up and a quality tripod, shake could not be contained.
FA600Plus stacked converters
Above with Pentax 2x-L converter stacked with the AF 1.7 adapter (converter). This is a retake using Car hood instead of tripod for enhanced stability.xx

Below is Pentax A*400 f/2.8 results

A*400 + 0
Above no converter
a400 + 1.4
Above with Pentax 1.4x-L converter
Note: The above photo seemed bad so I did a retake a couple days later and it seems excellent.
Above with Pentax 2x-L converter
a400 +2x+1.7x
Above with Pentax 2x-L converter stacked with the Pentax AF 1.7 adapter (converter)

Below is Pentax FA*300 f2.8 results

FA300 + 0
Above no converter
fa300 + 1.4
Above with Pentax 1.4x-L converter
Above with Pentax 2x-S converter
fa300 +2S+1.7x
Above with Pentax 2x-S converter stacked with the Pentax AF 1.7 adapter (converter) (shake evident)
fa300 +2x+1.7x
Above with
Pentax 2x-L
converter stacked with the
Pentax AF 1.7
adapter (converter)

Sorting out long lenses is always a challenge. Few are ever compared, and in isolation it's impossible to tell what is good and what is not so good. Likewise it is even more difficult to identify the sweet spot for each piece of glass. If you have a long lens its sort of a given that you will be pushing the envelope to reach out even farther. You can accomplish this by either aggressively cropping your photos (digital crop I call it) or optically cropping them by using a teleconverter that will effectively make your lens seem to have a longer focal length than it really does.

What I've done here is accomplish a 'shoot off' at a fairly long range---675 yards to my reckoning. The target was a Kubota excavator parked on the next ridge. I optimized the photos to read the printing on the excavator. I took photos first with no converter, and then with progressively more powerful ones, finally stacking a couple of them.

Neither the lenses nor the converters are current Pentax production items, as Pentax does not currently product any converter or any lens more exciting than a 300mm f/4, which is decidedly unexciting. There are announcements on Pentax's part for a long lens--a DA 560 (details unknown at this writing) as well as a weak converter with Auto focus automation.

There are clearly lessons to be learned from the exercise. First off one should not be afraid to use converters where appropriate. Cropping in the camera makes it easier getting the focus and the exposure right because more extraneous matter is excluded. This was particularly noticeable in this set up because I was shooting through a hole in the brush and trees. The interference was much more of a problem with the shorter configurations. Another ting that became clear to me was how critical the lighting was. I chose a cloudy day, to keep the contrast down, but the clouds were fairly thin and over the time I was taking the sequences, the light varied considerably, and often made a critical difference between success and failure of the photos. Finally it became clear that when you push out there with effective focal lengths of 1000 mm and beyond that a good tripod even with use of the mirror lockup, was not sufficient to prevent resulting vibration and camera shake. Try as I might, I was simply unable to get a non-shaky photo with the FA*600 and stacked converters. (a 2x followed by a 1.7x) When I resort to a pair of quilted coveralls on the hood of my car, I was then able to get a shake/vibration free photo. I did use mirror lockup sequence and remote release in all cases. It seemed to work best when I specifically supported the camera as well.

With the FA*300, I varied the formula a little. I have a Pentax-A 2X-S intended for lenses 300mm and less that I threw in the mix. The two longer lenses got only the Pentax-A 2X-L (for Long) documented for lenses 300mm and longer. Since the FA*300 is right on the borderline it apparently can be used for either. I think in the bigger picture the truth is that the Pentx nn-L converter will work physically with some 300mm lenses and not others. Indeed the ONLY 300mm lenses it will work with are the exotic f/2.8 kind because of the protruding element. It's beyond the scope of this article to figure out which works the best, but I think it's sort of normal to use the "L" converter if you have it, and one of the lenses that it works with. I had some problems with my test photo with the 2x-L, but on the retake day, the 2x-L worked fine stacked with the AF 1.7 adapter so I surmise it works well alone as well.

I rounded up these lenses on the second hand market, and actually bought the A*400 in recognition of the possibility that I might never find an FA*600. If it hadn't of been for that, I wouldn't own both. However, now that I have both, I will certainly keep them. The 400 and the 600 are both heavyweights, literally and metaphysically. They weigh 6kg and 6.8kg respectively. The 600 is one/third longer and an order of magnitude more difficult to use. I had little shake or vibration issues with the 400. I attribute this in part to the fact that physically it a lot shorter than the 600 and simply doesn't have the urge to rock around as much. When you get out there in distance it doesn't take much jitter to blur the photo, and you just can't get a shutter speed fast enough to stop the action. One can argue that I didn't have serious motion/vibration issues until I got out there beyond the range of the 400 and to some extent this is true, but it was also an issue with the FA*300 so I am not sure that is the whole story.

It even took special care with the 'carhood' support. I used two clothing items. One to support the heavy end of the lens and another directly under the camera. the hood was conveniently rounded so I could push the whole thing forward and backwards to get the desired elevation. I even tried using a 'jack leg' from the camera down to a tripod leg but this didn't seem to help much. What I didn't try was literally 2 tripods. I have an idea this would work but haven't tried it.

As between these, the 300 is a choice for the casual photographer. Even the f2.8 configuration is light enough to be hand held in a pinch, and works well with a monopod in any event even with a 1.4x converter. I've used slow 400's in the past and have been singularly unimpressed. They aren't long enough to work without a converter and are too slow to use with one. Obviously the 400 f/2.8 is an exception. With an F/2.8 speed, it has put a converter on me, written all over it. You can look at the pictures and draw your own conclusions, but I don't think stacking them gets you anywhere.

More information

- - Updated 12/12/2015
- - Updated 12/18/2012
- - Updated 5/4/2012