More Sigma 70mm/Kenko x2 TC test shots.. OK broke out my feeble tripod and tried some slightly more precise testing-not that I'm very good at it. Took a shot of a dead flower with the...

Ugly Hedgehog - Photography Forum

Home Active Topics Newest Pictures Search Login Register ☰

More Sigma 70mm/Kenko x2 TC test shots...

Page 1 of 2 next>

Mar 13, 2015 16:31:48 #

BobR Loc: Norwalk CT USA

OK broke out my feeble tripod and tried some slightly more precise testing-not that I'm very good at it. Took a shot of a dead flower with the Sigma 1:1 then with the Sigma/ Kenko combo at 1:1. Then I took a shot of my wheel with the Sigma and another with Sigma/Kenko. Here they are. Im pleased with the Kenko so far and surprised since everyone says how a TC degrades performance-especially a cheap one. I say this- I couldn't get a decent picture out of the Kenko on either of my zooms but it works great on the macro- I dont have the patience for using "live view" and a tripod which I'm sure I would need. Bob

Sigma 70mm 1:1

(Download)

Sigma and 2x Kenko 1:1

(Download)

Sigma 70mm cropped

(Download)

Sigma70mm+ Kenko

(Download)

Sigma 70mm before crop

(Download)

Mar 13, 2015 18:17:10 #

Erv Loc: Medina Ohio

Nice test set Bob. I do see the tree is just a little sharper without the TC. But that is nothing to get excited about. I use mind all the time on the 80-400. Now I have to drag out the 105 and give it a try. I always thought they were for reach. I always find something on the site to stir my mind! Thank you!!!

Mar 13, 2015 18:32:01 #

Nikonian72 Loc: Chico CA

Enlargement of Sigma and 2x Kenko 1:1 image looks quite good. You may be onto something!

Would you be so kind as to repeat images #1 & #2, and measure Working Distance for each? Thank you.

Kenko 2x Teleplus DG Pro-300 TeleConverter

Mar 13, 2015 18:33:19 #

BobR Loc: Norwalk CT USA

Thanks Erv! I think yeah it might be a tiny bit less sharp. Unfortunately I got the focus point off a tiny bit so you cant use the same points to go by. Still its nice to double my working distance. Thats one of the cool things about using a TC for macro. You can double your working distance at 1:1 or have the same working distance at 2:1! Bob

Mar 13, 2015 18:38:14 #

Nikonian72 Loc: Chico CA

Compare:
Exif info image #1:
Camera Model: NIKON D7100
Image Date: 2015-03-13
Focal Length: 70.0mm
Aperture: /29.0
Exposure Time: 0.017 s (1/60-sec)
ISO equiv: 100
Exposure Bias: -0.67 EV
Metering Mode: Center Weight
Exposure: aperture priority (semi-auto)
White Balance: Auto
Flash Fired: Yes

Exif info image #2:
Camera Model: NIKON D7100
Image Date: 2015-03-13
Focal Length: 140.0mm
Aperture: /29.0
Exposure Time: 0.017 s (1/60-sec)
ISO equiv: 100
Exposure Bias: -1.00 EV
Metering Mode: Center Weight
Exposure: aperture priority (semi-auto)
White Balance: Auto
Flash Fired: Yes

Looks like the camera is AWARE of the 2x TC added to 70-mm lens.

Mar 13, 2015 18:44:49 #

BobR Loc: Norwalk CT USA

Nikonian72 wrote:

Looks like the camera is AWARE of the 2x TC added to 70-mm lens.

Yes the camera is!
As for the working distance working distance its doubled at 1:1 with the TC vs without it. I measured this previously to be sure. If your curious as to the exact WD I'll measure it again.
As to the viability of TC's and macro- I saw this gentleman's macro shots with TC's, I was encouraged to try it myself.
http://www.mplonsky.com/photo/Macro-telecon.htm

Mar 13, 2015 18:49:03 #

Nikonian72 Loc: Chico CA

BobR wrote:

The working distance is doubled at 1:1 with the TC vs without it. I measured this previously to be sure. Bob

MFD to capture 1:1 with a 70-mm macro lens should be 105-mm = 4.13-inches.
To capture 1:1 with Kenko 2x TC + 70-mm lens, is Working Distance 210-mm (8.25-inches)?

Mar 13, 2015 18:54:27 #

BobR Loc: Norwalk CT USA

Nikonian72 wrote:

MFD to capture 1:1 with a 70-mm macro lens should be 105-mm = 4.13-inches.
To capture 1:1 with Kenko 2x TC + 70-mm lens, is Working Distance 210-mm (8.25-inches)?

Is that to the front lens element? Reason I as is because it doesn't seem like 4.13-in or 8.25-in, but the front element is tucked away from the front of the lens.

Sigma 70mm f2.8 EX DG Macro Lens

Mar 13, 2015 19:33:55 #

Nikonian72 Loc: Chico CA

BobR wrote:

Is that to the front lens element? Reason I as is because it doesn't seem like 4.13 or 8.24 inches but the front element is tucked away from the front of the lens.

Working Distance is from lens front element to subject;
Focusing Distance is from sensor plane to subject.

I am not familiar with this lens. Does the front element move DEEPER into lens body at MFD?

Mar 13, 2015 20:02:12 #

BobR Loc: Norwalk CT USA

Nikonian72 wrote:

Does the front element move DEEPER into lens body at MFD?

No it does not. The lens extends fully out (like a zoom) at MFD. With the ring flash on its 1 1/2 inches to the front element though so working distance is deceptive.
Measured at 3-1/8 inch working distance at 1:1 and twice that - 6-1/4 inches with the Kenko 2x TC added.

Mar 13, 2015 20:49:31 #

Nikonian72 Loc: Chico CA

BobR wrote:

Measured at 3-1/8 inch working distance at 1:1 and twice that - 6-1/4 inches with the Kenko 2x TC added.

I am still uncertain as to your chosen measurement point. If lens front element remains at fixed distance from lens filter threads, then you can mark lens barrel at plane of front element. This will be your measuring mark for Working Distance.
3.12-inches = 79-mm; 6.25-inches = 159-mm. These MFDs seem short.

Mar 13, 2015 21:13:15 #

BobR Loc: Norwalk CT USA

Nikonian72 wrote:

3.12-inches = 79-mm; 6.25-inches = 159-mm. These MFDs seem short.

Yes the front element remains fixed in relation to the filter threads. I measured from the front of the front element to the subject at MFD. I wish the distance was as you stated but its not. I just rechecked my measurements to be sure. Bob

Mar 14, 2015 02:29:37 #