Quality issue with TC

Just shot this with the Pentax 50-135mm and Pentax AF 1.7 TC. Anyone see a drop in IQ due to the TC?




Wide open indicated f/4.5

Regards

Have you a control image taken of that subject without the TC per chance?

Good point!! No actually. I was basically looking to see if anyone thought that this image showed signs of having a TC attached.

I will do two more. With/without TC.

Regards

Also, it might be helpful to show a 100% crop on an in-focus area

Two 100% crops:

without TC




with TC




Only basic levels adjusted. No sharpening. Both f/8

Regards

Hi,

The with TC looks softer to me.

Could you post an example of the "without TC" blown up to the same size as the "with TC" example. That would give a better idea if there was any advantage to using the TC and not just blowing up the original.

Greg

There is definitely more detail in the non-TC image...

These are 100% crops of the original jpg. To blow up the non TC to the with TC means pixelation.

Unless I'm missing something. If so let me know.

Regards

Hi,
Talking from my perspective, I try to make the subject fill the view finder so as to get the maximum size image on the sensor, obviously by moving nearer or further away. However if I can not get any closer and using the same lens then I must use a converter to get the maximum size image on the sensor.

My interest was in trying to see if the non TC image crop is better than the TC image when viewed at the same physical size on the screen.

Bit convoluted but I hope you understand my meaning
Greg

I've opened both pictures in Elements and matched their physical size by zooming in and out,133% and 75% if anything the No-TC version still has a slight edge over the TC version, but only very slightly.

Greg

Accepted Greg. My original post was more of a "blind loudspeaker test".
Which speakers are you listening to?

Does it look that bad whereby someone could say it had a TC on the lens?

Regards

Honestly, I am sure nobody could say that there was a TC behind the lens in your flower picture. To me, both focus and exposure look spot on.

On the subject of t/c i shot this one over easter with my Pentax F 1.7 converter I aquired last year. I used it with the DA* 60-250 , and I am quite pleased with the results.