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In anticipation of getting a decent TC for my DA*300, I was tempted to try out a A-1.4xS TC courtesy of @georgecape . Perhaps not ideal given the manual focus, but perhaps a good test of likely performance from the HD 1.4x WR TC. Have decided to go for HD 1.4x AF WR from this image quality and the desire to have AF. George got to try out the DA-15 for a few weeks in exchange.

I played around a bit with native crops compared to the 1.4x and an old 2x TC that I picked up a year ago. The reference lenses are the DA*300; a Tak 200 f/3.5 preset; and a Tak 500 f/4.5 preset. All the lenses are very sharp although the older Tak 500 is a bit prone to CA.

Typical processing was to enlarge native and 1.4x images to same size as 2x TC image, and then compare side by side using Faststone.

Observations so far. Resolution with 2x TC is the highest by a fair amount, but the image quality of the 1.4xS appears slightly better (or at least more pleasing). Both TC's are a significant improvement on the native with cropping. And finally, the TC don't seem to degrade the image much, but rather just amplify the poor lens qualities. So with the really sharp lenses used here, the IQ remained very high in all cases.

The DA*300 native view:


And then the view cropped up close: Order 2x ; Native ; 1.4x


The Tak 500 native view:


Order 2x ; 1.4x ; Native


And then a similar comparison using the Tak 200

Order 1.4x ; Native ; 2x

Thanks for taking the time to post your results. I'm a bit of a tester also and Iike to compare images in this way as well.

I am curious though if you have compared your native shots with the TC shots after cropping it and then resizing back to full resolution using lanczos or some other similar algorithm?

Whenever I've run my own tests, I have been much less impressed with the TC results, especially considering the loss in speed (light), handling, and magnification of lens flaws.

Just some of my random thoughts. I find it's always hard to compare images unless they are at or near the same resolution.

Thanks @Arrvon for useful comment. I think I did the opposite and down-sampled the large images to the cropped resolution in some, so took the time to redo the aerial mount resolution as this was the best for outright resolution test. Seemingly still the same indicative result, although not as much blocky pixelation on the crops with the higher resolution.

Hope HD 1.4x AF WR TC as good if not better, as one now on order for late next week...


TC comparison DA300-4 Aerial Mount 2 by KevinR38, on Flickr


TC comparison DA300-4 Aerial Mount 3 by KevinR38, on Flickr

Thanks again for posting your results. I find that it's a very useful resource to have rather than just someone's text.

I also agree with your assessment of results and am impressed with the TC results. I may need to dust mine of and try them with a better quality lens or two.

Just curious what the old 2x you used was? I have an d vivitar 2x macro and it seems to do a decent job for what it is.

It is a SAITEX Auto 2x TC KR (Japan). I got it from the same source as the Tak 200 f/3.5 for a very economical price. They didn't have unrealistic expectation as it was a family hand-me-down. I just wanted to play, and perhaps hack the TC body for some other purpose if it was lousy IQ. But now think I'll keep it for manual lenses. I also have an old A-1.4xL, but this only works on Tak 500, so 2x may have some use.

I have had a Vivitar 2X Macro Converter for several years. Worked pretty good on film. Haven't played with it yet on my K5 or K5-IIs. I haven't played with my Tamron 1.4x converter yet either with the new cameras.

Edited ... I had posted something but I does not matter now.
Waiting to see your tests with the DA*300 and the new HD 1.4 X TC, as I have ordered one myself ... since June 17 !! (not here yet).

JP

Finally getting to doing an update on this with new DA-1.4x AF AW teleconverter included alongside native and old MF 2x TC. Don't have access to Pentax A-1.4xS from @georgecape, but impression is that new DA-1.4x is very similar performance, just with all the convenience of AF.

The performance of the DA*300 with these TC versions is remarkable, and it seems to confirm my view that a good TC just magnifies lens defects. And the DA*300 doesn't have much of that. So TC IQ degradation is minimal. Obviously the IQ suffers a bit from addition issues of subject motion, atmospheric distortion and camera vibration as the magnification becomes enormous.

Then started playing with double up of 2x and 1.4x not expecting too much. Was I wrong. The IQ seems to hold up remarkably well, and the old Saitex A-2x is not too bad.
Got to say, the prospect of an 840mm f/11 lens (equivalent wide open f/4) at this IQ is attractive for some uses.

The view comparison only cropped horizontally. (ie full vertical FoV)



And then a zoom in on the angle graduation plate with each image resized so that the view is the same number of pixels in each case (600x600 from 2.8x TC as default view)



And then a real target bird who was kind enough to be sitting there for the whole show
1/500s, f/4 (f/11 eq), ISO400

The stacked converter shot is pretty impressive. I use a K 300/4 with a Pentax A 2x with good results as far as sharpness is concerned. The one drawback with my combo is the CA can be downright nasty and uncorrectable sometimes. A bird against a cloudy sky would look horrible.

That has been one of my previous issues with TC and massive CA. My previous playing with Tak-500/4.5 and TC combinations gave significant CA, while Sigma170-500 just becomes way too soft (and too dark starting at default f/9.5) to be usable. The DA*300 seems to have very few defects to magnify, and this shot is wide open. There is a very slight amount of Magenta/Green fringing starting on the edge of the white wall but hardly noticeable at this size.

Kevin your A-2x seems to be magical... makes me want to add one to my collection.

Thank you for doing these tests, and doing them well. Very useful.

And one more addition to this, with the FA*600/4 in my hands (thanks to user Johan Kruger) for a few weeks, I simply cannot miss out on doing a quick comparison (albeit in slightly different lighting conditions)

FA*600 native at f/8; then FA*600+DA-1.4x; and then a crazy shot at FA*600+DA-1.4x+A-2x (but this was not steady enough to post crop view.

The FA*600 is sharp, no question about it...

The view comparison only cropped horizontally. (ie full vertical FoV)



And then a zoom in on the angle graduation plate with each image resized so that the view is the same number of pixels in each case (600x600 from 300x2.8TC or 600x1.4xTC as default view)

Thanks for the test Kevin.

Awesome Kevin... thanks for taking the time.