TEST : Pentax-DA smc 55-300mm f/4-5.8 ED + Jessop 1.7x TC

TEST : Pentax-DA smc 55-300mm f/4-5.8 ED + Jessop 1.7x TC

Camera K-5 at f/8 & 1/160th : Brolly Flash : 80ISO : Tripod

100% Crops from Camera jpgs both given the same slight PP tweak

1st shot with Jessop 1.7x TC from 5.4M at approx. 230mm on lens

2nd shot NO TC from 3.43M at approx. 230mm on lens (adjusted slightly to
give same image size).

Result/Conclusion : LOSS DUE TO TC IS NEGLIGIBLE.

2nd shot is slightly brighter which is mainly due to
the flash being left on the same power instead of
being reduced by 1 stop.

I have used several shots for the comparison which aren't posted here
and the two posted are 800 square crops from full size images.

Both Manual Focus by Live View
Extra shots taken +/- 40mm either side
to check focus.

AF also works perfectly with this LENS AND TC
Shots at 300mm should be similar.

Complete Exif Data inc. name of lens seems to
be on the original JPGS some gets lost on the
crops.

Shot 1 with Jessop 1.7x TC




Shot 2 No TC



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Algernon

In the other thread you mentioned that this TC is/was sold under several other names than Jessops - can you identify any of them, because it looks like a useful TC to have?

John

I'm still checking on that. The next check is SDM I know
the Jessop one works well with the Sigma 150-500mm but
have to check it again with the Pentax DA* 300mm.

The usual one for the DA* 300mm is the Tamron 1.4 which I
have, but it's not as sharp with the 55-300mm

A lot of these TC's look the same, but don't work the same

If it turns out that I have two both the same I'll be selling
one for around what I paid for them (c. £150)

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I'm impressed. On those images there appears as you say no significant quality loss, and the test conditions are harsh to the teleconverter as well - it might be fairer to compare with/without shots from the same distance with the lens only image enlarged similarly. That after all is the choice we generally face - put a converter on or do without and crop.

Just looking through some shots taken recently with the
Pentax-DA smc 55-300mm f/4-5.8 ED + Jessop MC 1.7x Pz/AF TC for another thread.

These two were from a few weeks back when the weather wasn't
as bright as it is today.

Rabbit K-5 400ISO Quick grab shot.




100% Crop




Blackbird K-5 800ISO





I've also been using the TC with the Sigma 150-500mm without any problems.
It works with the SDM on the DA*300mm f/4 but you
keep having to press the AF button to get exact focus.

It's identical to the Pz-AF 1.7x Teleplus SHQ TC which I also have so because
I don't need two with the same spec/performance I'll be putting it
up for sale in Classifieds shortly.


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I might as well add a couple of hand held sots taken with the Sigma
150-500mm plus the Jessop MC 1.7x Pz/AF TC last week.
K-5 400ISO









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The 55-300mm + TC came out slightly sharper than the
Sigma 150-500mm without TC at 450mm and f/7.1 on the
Sigma.




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This screen grabs 1000pixels wide so here's a direct link to it.
Very slight difference in size which doesn't really matter.
Both shots were the best of 4. The Sigma will probably be better
at f/8 it is a very good lens.

http://uppix.net/9/9/d/9b23a400cbab851b5df08e91cf51b.jpg

The Pentax 55-300mm + Jessop 1.7x TC also gives a
narrower field of view than the Sigma set at 500mm.

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