Stacking 2x and 1.4x TC

[Neon Rosell II]

Today I had the opportunity to experiment on staking a 2x and a 1.4x Kenko TC on my 300 mm L f4 IS lens to give me a whooping equivalent of 840mm. Since I knew the sweet aperture setting on my bare lens is f 5.6-8, I just shot with this values. Using a higher f 10.0 on this shot which equates to an f 28.0 for added DOF giving me slow shutter speeds of 1/20-1/60 sec due to changing light intensities from a slightly overcast skies.

Note: staking TC will not register a right exif data, hence you have to multiply the aperture readings by the TC's magnification values.

The wind was also slightly gusty so I have to time my shot when it was least blowing. The Live View was very helpful in this regards as when you magnify the view to 5x slight movements can be easily noticed.

Here is a cropped shot to show the amount of detail this setup has retained. Now!! who needs a 500mm when you can have 840mm ;D

40D + 840mm L f11.2 IS "Kenmonster", f 28.0, 1/50 sec, ISO 200, Manfrotto 055PROB, 393 Gimbal Head, Remote switch, Live View, Manual Focus, Manual Exposure

[Romy Ocon]

I'm surprised with the IQ with all those TCs, Neon.... how do 100% crops look?

[Neon Rosell II]

Mar 30, 2008 0:30:11 GMT Romy Ocon said:

I'm surprised with the IQ with all those TCs, Neon.... how do 100% crops look?

Here's a processed 100% crop.

[William Lim]

Good IQ for stacking the 2x and 1.4x TC's. Which TC was attached to the lens first, the 2x or 1.4x?

[Romy Ocon]

Not bad at all.... looks like the combo is useable for these types of shots, when the subject allows your to fine tune MF.

Mar 30, 2008 4:47:40 GMT Neon Rosell II said:

Mar 30, 2008 0:30:11 GMT Romy Ocon said:

I'm surprised with the IQ with all those TCs, Neon.... how do 100% crops look?

Here's a processed 100% crop.

[Neon Rosell II]

Mar 31, 2008 7:39:26 GMT William Lim said:

Good IQ for stacking the 2x and 1.4x TC's. Which TC was attached to the lens first, the 2x or 1.4x?

Thanks William!! The 2x was first then the 1.4x, I have no Idea if it would have mattered if it was in reverse And Both are Kenko brand

[Luis (Chito) Limchiu]

Correct me Neon If I am wrong but the f28 really is just exposure wise, since i don't think the image sharpness would be like a real f28 meaning I don't see how the aperture opening can be affected by the TC. Anyway Nice IQ, Was it a super bright day? Looks like i will be giving this a shot soon.

[Neon Rosell II]

Mar 31, 2008 11:10:44 GMT Luis (Chito) Limchiu said:

Correct me Neon If I am wrong but the f28 really is just exposure wise, since i don't think the image sharpness would be like a real f28 meaning I don't see how the aperture opening can be affected by the TC. Anyway Nice IQ, Was it a super bright day? Looks like i will be giving this a shot soon.

Yes, Doc Chito, you just slowed down your lens when you added a TC making less light going to the camera's sensor, as you add a TC you have to multiply the aperture value by the magnification factor of the TC. The aperture value shown by your camera is a factor smaller as you add a TC. i.e. if your camera shows 4.0 and you add a 2x TC the equivalent aperture would be 8.0. So, if you want a higher DOF you have to stop down from the widest aperture of 8.0 making your shutter speed suffer in th process.