# Lens naked or 1,4x ?



## GP.Masserano (Jul 18, 2016)

A question of technical for the super experts. 
*Canon EOS 7D MK2 + new 100-400 L II. 
*
First test: photo taken at 400mm.
Second test: same photo taken by mounting the doubler 1.4x 

To obtain an image of the subject of equal size, will be sharper than the picture taken with the doubler or one taken with the objective "naked" cropping what is necessary? 

In other words: to have a higher ratio of reproduction of the subject (animal), it is advisable to install the doubler on camera or crop then the image with PS on my PC ?

Thanks
GP


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## greger (Jul 18, 2016)

I'm guessing that you want to know if it is better to use a 1.4 Extender on a lens, or is cropping better. I haven't tried the 1.4 on my 100-400 mark l yet. The doubler - 2 x Extender didn't give me a usable picture. The 1.4 might. It's fine on my 70-200 f4 IS USM lens. I used it all the time. I think the 1.4 will work fine with the 100-400 mark ll and the 7D ll. Then you could crop in PS and have a very nice picture enlarged bigger in size than cropping a picture taken with the 100-400 ll without the 1.4 Extender.


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## Mikehit (Jul 18, 2016)

The fact that this is much-debated suggests to my that the differences are minimal. I have the 1.4MkII with the set-up you mention and not seen a big difference. 
The Mark III Canon extender is said to be better again and the few comments I have seen suggest it does start to show some benefits over the naked lens.

If you are talking about 'doubling' then you need the 2x extender and the MkIII really is a significant improvement over the Mk II by all accounts.


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## neuroanatomist (Jul 18, 2016)

Will the picture with the TC be 'better' than bare lens cropped? 

The 1.4x will increase final resolution, so all else being equal the resulting image will be sharper. The extra resolution only matters if there are additional details to be resolved, but with animals there is generally ample detail. The 1.4x will slow down AF, substantially limit your available AF point coverage (only center point selectable), and will cost you a stop of light. Depending on the subject motion and your desired framing, the impact to AF performance may outweigh the increased sharpness. Likewise, if you're already at a high ISO to get the necessary shutter speed, getting that stop back means reducing shutter speed (more chance of motion blur) or increasing ISO (more noise), either of which could reduce perceived sharpness in the final image. 

So, the answer is 'it depends'. If you've got plenty of light, and a subject where you don't require the fastest possible AF and have time to focus-recompose, you're better off using the 1.4x. In lower light with fast-moving subjects, you're better off using the bare lens and cropping. 

Personally, I shoot mainly birds with a 1D X and 600/4 II, and I usually use the 1.4xIII (>80% of shots). But the resulting 840mm f/5.6 still gives me all the AF points, and the resolution boost is greater because the 600 II is sharper, and the pixels are bigger. The 600/4 + 2x is more analogous to using 100-400 + 1.4x, and personally I use the 2xIII for only about 5% of my shots, and as stated above that's in good light with slower subjects.


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## GP.Masserano (Jul 19, 2016)

neuroanatomist said:


> Will the picture with the TC be 'better' than bare lens cropped?
> 
> *[size=8pt]The 1.4x will increase final resolution,[/size]* so all else being equal the resulting image will be sharper. The extra resolution only matters if there are additional details to be resolved, but with animals there is generally ample detail. The 1.4x will slow down AF, substantially limit your available AF point coverage (only center point selectable), and will cost you a stop of light. Depending on the subject motion and your desired framing, the impact to AF performance may outweigh the increased sharpness. Likewise, if you're already at a high ISO to get the necessary shutter speed, getting that stop back means reducing shutter speed (more chance of motion blur) or increasing ISO (more noise), either of which could reduce perceived sharpness in the final image.
> 
> ...



Many thanks for your very detailed answer.

In summary : little sharp difference but loss of autofocus on all points: I understand well? 
Therefore little advantage and great disadvantage...

Are you sure that the 1,4 III* increase the final resolution*? 
Really the 1,4 III is so obviously better than the previous ones?

It would be nice to do some tests with optical aims, so as to definitively resolve the issue!
For example I read in a magazine that the 70-200 2.8 II with 2X II was even better than the 400 f 5.6!!!


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## neuroanatomist (Jul 19, 2016)

GP.Masserano said:


> In summary : little sharp difference but loss of autofocus on all points: I understand well?
> Therefore little advantage and great disadvantage...



Correct. Except that in your first post, you asked which would be sharper – how much that advantage matters depends on how important you find that extra bit of sharpness. 




GP.Masserano said:


> Are you sure that the 1,4 III* increase the final resolution*?
> Really the 1,4 III is so obviously better than the previous ones?



Both the 1.4xII and 1.4xIII would increase the resolution – that's just physics. The MkIII is optically pretty similar to the MkII, the main changes with in AF algorithms (optimization for the MkII super tele lenses). The MkIII does have less distortion and also less CA (which can increase contrast and resolution in some cases).


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## GP.Masserano (Jul 19, 2016)

It would be nice to do some tests with optical aims, so as to definitively resolve the issue!
For example I read in a magazine that the 70-200 L 2.8 II with 2X II was even better than the 400 L f 5.6.


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## StudentOfLight (Jul 19, 2016)

GP.Masserano said:


> It would be nice to do some tests with optical aims, so as to definitively resolve the issue!
> For example I read in a magazine that the 70-200 L 2.8 II with 2X II was even better than the 400 L f 5.6.


Here is are test charts (i.e. closer shooting distances) on 18MP Canon EOS 60D:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=687&Camera=736&Sample=0&FLI=5&API=0&LensComp=278&CameraComp=736&SampleComp=0&FLIComp=0&APIComp=0


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## AlanF (Jul 19, 2016)

A lot depends on the sensor. On FF with 18-24 mpx, I like using the 100-400mm II + 1.4xTC III. But, with the 5DS R or 7DII, I prefer the bare lens. The smaller pixels are more sensitive to the smaller aperture, f/8 is above the diffraction limit, more sensitive to the loss of IQ of the lens, and more sensitive to shake. So, the trade-off of extra length vs loss of IQ on using a TC gets worse for smaller pixels.


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