[imtheguy]

Hi Lee,

I've got the 2x Sigma TC. It will autofocus pretty well on the Sigma 500 f/4.5. I've not systematically tested cropping vs. the TC. My impression is that conditions have to be really prime to make it worthwhile to use the 2x, by which I mean a lot of light, a stable tripod, and a subject that isn't moving. I'll take the Sigma 1.4x or Tamron 1.4x with me when I'm out for a walk with my Sigma 500 but not the Sigma 2x. In that sense it is a specialized and infrequently used piece of my kit. I'll be interested in any other feedback you get.

Russ

I have now played with a new Sigma 2x TC for a week and the IQ is better than expected but of course not as sweet as the 1.4x. As far as AF, not a chance with my K-5sii. Just wondering if you have the same TC (APO 2x EX DG) and which body you get AF with? Its not a requirement at 1000mm but always a nice to have. Thanks for the lead!

[normhead]

Very cool...I briefly tested the Pentax 1.7 on a few lenses and the purple fringing was so bad, I never considered doing another tests. Those are encouraging results. A number of people on this site have argued (and ad nauseum) that these results are impossible. My own theory that they should be quite possible has been continuously drowned out. Incidentally, yours in the first test done on a test chart. I'd be interested in seeing how your TC did at infinity. The one thing we have found, the TC is very useful for with some of our lenses especially for macro lenses, is for close ups, or anything close to the camera, say within 20 feet.. At longer ranges we find the TC images to be not as good. So, I'd be happier with this if you also took some images at distance the to see if you still think the TC performs as well as it does close in.

[oeriies]

I have now played with a new Sigma 2x TC for a week and the IQ is better than expected but of course not as sweet as the 1.4x. As far as AF, not a chance with my K-5sii. Just wondering if you have the same TC (APO 2x EX DG) and which body you get AF with? Its not a requirement at 1000mm but always a nice to have. Thanks for the lead!

I'm shooting with the classic K-5. I'm not saying I get successful autofocus everytime. The combo needs decent light and an image with high contrast zones. Otherwise it will hunt. For example, on the test chart at 30 ft. it will nail focus every time if the center point is on the edge of the chart where there is a dark black line and a tiny depth difference between the chart and the larger piece of cardboard to which I have it glued. However, with center point focus on the center of the chart with only small detail it will hunt 2/3rds of the time. Even there it will nail it with enough tries. It seems much more reliable if it is prefocused approximately than if it is running through its whole range. So in use I'll find the highest contrast area I can that is close to the same distance as my target (if the target itself isn't very contrasty), get autofocus with the center point, then shift to the target and autofocus again. I haven't used the 2x TC a lot, maybe no more than a half dozen times, but it always auto-focused well enough for me to use it without switching to manual focus. In fact, I would have sold it if it didn't autofocus because I'm no good at that with a long telephoto lens.

Is yours not engaging autofocus or just trying to focus but always failing? If it is the former, I had that problem with mine when I first got it. I could hear the screw drive in the TC moving, but the lens wasn't doing anything. I dropped it off at Sigma in Ronkonkoma. They fixed it in 10 minutes. You never get to talk to the technicians there -- only someone in the front office who serves as a go between -- so I'm not sure exactly what they did or what the problem was. My guess is that the flange or some other part needed to be tightened.

Russ

[oeriies]

Very cool...I briefly tested the Pentax 1.7 on a few lenses and the purple fringing was so bad, I never considered doing another tests. Those are encouraging results. A number of people on this site have argued (and ad nauseum) that these results are impossible. My own theory that they should be quite possible has been continuously drowned out. Incidentally, yours in the first test done on a test chart. I'd be interested in seeing how your TC did at infinity. The one thing we have found, the TC is very useful for with some of our lenses especially for macro lenses, is for close ups, or anything close to the camera, say within 20 feet.. At longer ranges we find the TC images to be not as good. So, I'd be happier with this if you also took some images at distance the to see if you still think the TC performs as well as it does close in.

I'm out of town now and won't be home until Friday. I'm glad to try it at infinity this coming weekend if we finally get some decent weather on Long Island and I can figure out how to go about it. According to the follow site, the hyperfocal distance of a 500mm lens at f/5.6 on an APS-C sensor is 7632.9 ft: Online Depth of Field Calculator It is going to take a pretty big test chart to fill the frame at a mile and half. Any ideas?

Russ

[normhead]

My test for infinity was to go to Opeongo lake and shoot the cliffs down the lake, probably a little over a Km away. What I've found with softer lenses it the cliffs look like they were done with a Photoshop watercolour filter. The shrubs and small trees on the side of the cliff provide me with some fine detail to examine or not examine because the lens isn't sharp enough to resolve them.

Or I guess you could paint a test chart on the side of a building or something.

[imtheguy]

I'm shooting with the classic K-5. ........

Russ

Thanks for the reply. No, I get not a peep out of my attempts but did not pursue after 2 minutes. But for the sake of research I will mount the classic k-5 body this time and make sure it was not just a user error on my part. If the rain stops and clouds part I may get out today.

[oeriies]

My test for infinity was to go to Opeongo lake and shoot the cliffs down the lake, probably a little over a Km away. What I've found with softer lenses it the cliffs look like they were done with a Photoshop watercolour filter. The shrubs and small trees on the side of the cliff provide me with some fine detail to examine or not examine because the lens isn't sharp enough to resolve them.

Or I guess you could paint a test chart on the side of a building or something.

My guess is that shooting a natural scene a Km away isn't going to allow a convincing IQ comparison of the Sigma 500mm with and w/o the 2x. But that's another way of saying it probably doesn't make any difference whether you crop or use a TC if you're shooting something over a mile away and expecting fine detail -- atmospheric diffraction will likely be the limiting factor rather than the lens itself. However, I do take your point that a test at 30 ft may not tell the whole story. I think about using a TC when I'm shooting water birds that are far enough away that I'm going to end up with a 100% crop to fill the frame -- that's probably a couple of hundred feet instead of 30. If I have time this weekend I'll check how the 2x TC performs relative to cropping at that distance.

[imtheguy]

As promised I have results.

Using center-point only:
o My K-5 will consistently AF using 2x TC on the Sigma 500/4.5.
o My K-5iis......not so much. Maybe 1 out of 10 tries on highest contrast target, never on things the k-5 will catch.
o AF even on the K-5 (as mentioned above) not as precise as MF but useful.

Basic settings are the same but I need to dig and see what may be buried in the menus.

Quality? I could not wait for the drizzle to stop so had to shoot iso3200 to get 1/400 on a swinging feeder. This is a 50% crop and includes some processing due to noise but now I am excited to see what it looks like in good light at a decent iso. I was actually just testing the focus on the feeder when the Wren dropped in. did not expect it to be within the DOF but seemed to be. Now I am occupied figuring out why the k5iis will not AF while the older body does. Love a good mystery.

[derekkite]

As promised I have results.

Using center-point only:
o My K-5 will consistently AF using 2x TC on the Sigma 500/4.5.
o My K-5iis......not so much. Maybe 1 out of 10 tries on highest contrast target, never on things the k-5 will catch.
o AF even on the K-5 (as mentioned above) not as precise as MF but useful.

Basic settings are the same but I need to dig and see what may be buried in the menus.

Quality? I could not wait for the drizzle to stop so had to shoot iso3200 to get 1/400 on a swinging feeder. This is a 50% crop and includes some processing due to noise but now I am excited to see what it looks like in good light at a decent iso. I was actually just testing the focus on the feeder when the Wren dropped in. did not expect it to be within the DOF but seemed to be. Now I am occupied figuring out why the k5iis will not AF while the older body does. Love a good mystery.

Seriously? I would have thought the k5 would be worse than the K5IIs. Very interesting.

[cmohr]

Do you have the K-5iis AF set for frame rate rather than accuracy??? Maybe need to set a user mode specially for the combo???

[oeriies]

As promised I have results.
This is a 50% crop and includes some processing due to noise but now I am excited to see what it looks like in good light at a decent iso. I was actually just testing the focus on the feeder when the Wren dropped in. did not expect it to be within the DOF but seemed to be.

Good image for the shooting conditions. Seems like there's a bit of front focus (bottom forward part of the feeder is sharper than the Wren) so I think you're going to get very good quality images with good light and perfect focus. Is that pasta in the bird feeder? Where's the marinara sauce?

This is from my Sigma 500mm 2x TC combo from last summer: http://i1093.photobucket.com/albums/i436/oeriies/ducks%20and%20birds/black-c...ffdockjuly.jpg

Russ

[imtheguy]

Seriously? I would have thought the k5 would be worse than the K5IIs. Very interesting.

Bright sunny day here so I tried the comparison again. Now the K5iis can hit typical subject with AF at least 1/2 the time but sounds much slower than the k5 which zips to the focus spot and stops. No question at this point, the venerable k5 body takes the cake. Also as expected in better light the AF is more accurate and crops of the little birds look good up to just short of 100%.

So I will start using the 2x TC for the Raptors and marsh birds at a distance and stay with the bare lens or 1.4x TC for little birds.

The difference in performance between the k5 and k5iis is perplexing. Next is to reset both to factory settings and compare one more time.

If anyone has a clue or suggestion to try for me to sleuth the difference in the bodies please throw it out here.

[imtheguy]

Do you have the K-5iis AF set for frame rate rather than accuracy??? Maybe need to set a user mode specially for the combo???

whoops, somehow I missed your question. I have looked at the AF.S and AF.C menu settings on both bodies and all are set at "1" for focus priority.

[imtheguy]

Good image for the shooting conditions. Seems like there's a bit of front focus (bottom forward part of the feeder is sharper than the Wren) so I think you're going to get very good quality images with good light and perfect focus. Is that pasta in the bird feeder? Where's the marinara sauce?

This is from my Sigma 500mm 2x TC combo from last summer: http://i1093.photobucket.com/albums/i436/oeriies/ducks%20and%20birds/black-c...ffdockjuly.jpg

Russ

not front focused....I was testing by focusing on the feeder when the bird landed and I just snapped it. Due to foul weather I was not trying to catch any critters at iso3200....except for that one.

Your Heron looks great and that's the subject I decided is perfect for this combo; large birds.

[PePe]

I'm shooting with the classic K-5. I'm not saying I get successful autofocus everytime. The combo needs decent light and an image with high contrast zones. Otherwise it will hunt. For example, on the test chart at 30 ft. it will nail focus every time if the center point is on the edge of the chart where there is a dark black line and a tiny depth difference between the chart and the larger piece of cardboard to which I have it glued. However, with center point focus on the center of the chart with only small detail it will hunt 2/3rds of the time. Even there it will nail it with enough tries.

This is pretty much my experience as well. For my use the hit rate is just not good enough. Therefore I regard this combo as a MF lens. Don´t really use the 2 x TC that often.