[e_hutchinson]

I'm looking for a 1.4x or 1.5x teleconverter to use with my K20D and Sigma 50-500mm lens. Does anyone have experience using a teleconverter with this SLR and lens combination that not only works but provides good performance? I have the old Pentax 1.7x and new Sigma 1.5x & 2.0x teleconverters, none of which will work.

Thanks.

e_hutchinson
Edwin D Hutchinson Nature Photography

[Ben_Edict]

In general I would not use a tc with that lens, as it gets too slow. But if you need to use one, the Sigma Apo 1.4x should do fine. You just have to remember to use the focal length limiter, to prevent damage to the rear element. As many people report, that the Bigma gets too soft at its longest focal length, an observatiob, which I tend to agree, though this can be fixed to my satisfaction in post-processing, it is doubtful whether a tc makes sense at all.

Ben

[e_hutchinson]

Thanks for the information. I have tried the Sigma APO 1.4x teleconverter but apparently without using the focal length limiter on the Sigma 50-500mm lens. I will try it again (correctly) and see how it affects IQ. I have a good copy of the lens so hopefully it will give satisfactory results with post-processing in those rare occasions when I need the extra reach.

Regards,
Ed Hutchinson
Edwin D Hutchinson Nature Photography

[e_hutchinson]

A change of subject, but still on teleconverters. It's my understanding from this forum that the Tamron F 1.4x Pz-AF MC4 teleconverter works well with the Pentax DA* 300mm f4 lens. Any comments on personal experience? If anyone knows where I can buy a copy of the TC I would appreciate the information.

e_hutchinson
Edwin D Hutchinson Nature Photography

[Mike.P®]

It's my understanding from this forum that the Tamron F 1.4x Pz-AF MC4 teleconverter works well with the Pentax DA* 300mm f4 lens. Any comments on personal experience?

These were taken with the Tamron MC4 and Pentax F* 300mm f4.5.
Although not the DA* they should give you an idea of what the TC can do.

[e_hutchinson]

Nice photos ... thanks for sharing them. I'm anxious to get a copy of the Tamron MC-4.

[Mike.P®]

Nice photos ... thanks for sharing them. I'm anxious to get a copy of the Tamron MC-4.

Will swap for the Pentax 1.7X

[Fl_Gulfer]

The Tamron MC-4 works on my Sigma 150-500 APO HSM also.

[e_hutchinson]

Mike ... thanks for the offer. I keep the Pentax 1.7x TC attached to my Pentax 100mm f2.8 Macro so I don't think I want to let it go.

[e_hutchinson]

Thanks for the information. I'm a "Tx_Gulfer." I do a lot of bird photography here along the southeastern Texas coast. In a month or two it's going to be interesting to see how my favorite rookery made it through the destruction caused by hurricane Ike. There are several pictures on my web site that were taken there last spring.

Ed
e_hutchinson
Edwin D Hutchinson Nature Photography

[BPT]

I have the sigma 50-500 as well as a sigma 1.4x teleconverter. In all I havent used the combo much real world since I found too much degradation in the quality of the shot. I hope to give it another shot this year and see if it is mostly due to skill level which I would highly suspect.

I can autofocus with good light with it, it is not so bad that way

Great for moonshots though

[e_hutchinson]

Very nice moon shot! Looks pretty sharp to me.

[Mike.P®]

Moonshot with my F* 300mm f4.5 with both the Tamron MC4 and Sigma 2X DG EX Teleconverters attached.
I reckon it would have been sharper still if I had used a tripod.

[Ben_Edict]

As this seems to be a moon shot thread , I have added another one. This was done with the Pentax AF tc 1.7x, placed behind a small 600mm (f/6) semi-apo telescope at the beginning of February.AF did not work, by the way. Camera was a K20. The tc did not add any false colours and the quality was very much sky-limited, as it was not really clear. In the original file you can identify craters down to 9km in diameter. I rotated the image to meet the upload limits... The sharpening artefacts are due to the pre-upload sharpening, may be I have done a bit too much there.

Ben