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Stacked 1.4's v 2x tc samples (1 Viewer)

I don't see your point about the magnification Roy.

A 1.4x converter gives 40% increase in mag and a loss of one f-stop.
Two stacked 1.4x converters would surely give 80% increase in magnification, and 2 f-stops loss of light.

Surely it is 1.4 +1.4 (40% + 40%=80%) rather than 1.4 x 1.4? hence the difference in magnification.

Steve
Steve, both combos lose 2 stops but stacked 1.4's do give 1.96 x mag, with one 1.4 tc you have a focal length of 420 (300*1.4) Now when you add another 1.4 tc to that set-up you have 420 * 1.4 = 588mm. (588/300 = 1.96).
I think I read somewhere that a 1.4tc is actually something like 1.416 so that it should come to 2x
 
If you did not want us to wander a little, like I did, you should have made it clear in your post camera setup.
Sorry about that Terry but if you read my post it does say 'Can you see any difference in IQ and if so which one do you prefer'.
 
Steve, both combos lose 2 stops but stacked 1.4's do give 1.96 x mag, with one 1.4 tc you have a focal length of 420 (300*1.4) Now when you add another 1.4 tc to that set-up you have 420 * 1.4 = 588mm. (588/300 = 1.96).
I think I read somewhere that a 1.4tc is actually something like 1.416 so that it should come to 2x

Yes, I see now Roy. Overlooked the fact that the second TC is also magnifying the Lens + 1tc by a factor of 1.4.

Cheers for the maths lesson,

Steve
 
Roy,

Be brave! Stack all three of your converters on the lens, manually focus using 5x magnification with Live View and use a remote release. It works!

Mike
LOL :-O That would give a focal length of 1176 with a field of view of 1881 on the 1.6 cropper. Have you seriously tried it Mike?

The reason why I posted this today was that I received the 2x tc this morning and I have sold the Kenko 1.4 but not yet dispatched - I wanted to make sure that I have not made a mistake (mind you I still have a old teleplus 2x that I could try with the 2x and 1.4, that would give me 1680mm 8-P )
 
LOL :-O That would give a focal length of 1176 with a field of view of 1881 on the 1.6 cropper. Have you seriously tried it Mike?

The reason why I posted this today was that I received the 2x tc this morning and I have sold the Kenko 1.4 but not yet dispatched - I wanted to make sure that I have not made a mistake (mind you I still have a old teleplus 2x that I could try with the 2x and 1.4, that would give me 1680mm 8-P )

Roy, all this stacking is doing me head in........:-O
 
I think I justified the 2x tc today John-Henry - the light was good so I stacked the 2x and 1.4x to give a focal length of 840mm. Results exceeded my expectations and I got AF as well (albeit sluggishly at times). see attached sample. This was a 5.3mp crop so not even full frame.
 

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I think you certainly did Roy, great shot.

The 300 is a fantastic lens and your experiments with it show good quality can be obtained from 300mm - 800mm+.

If anyone wanted just one lens for birding the 300 F2.8 would be an excellent choice.
 
Roy,

Sorry for the delayed response to your question. Yes, I have tried it and it does work. I stacked a Canon 2x, a Sigma 1.4x and a Jessops 2x all together on my 300 lens mounted on a tripod looking through a double-glazed window. Using the 5x magnification enhancement in Live View I manually focused on a distant tree on the horizon and used a remote release to take the picture.

Compare the following two images. Look carefully in the wide-angle view for the three trees on the hill above the roof heating vent above the white garage door in the centre. The close-up shot using the three stacked converters shows the middle tree full frame.

Admittedly I have not yet tried this "in the field". It was just an experiment to see what the lens was capable of. I was impressed!

Mike
 

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Roy,

Sorry for the delayed response to your question. Yes, I have tried it and it does work. I stacked a Canon 2x, a Sigma 1.4x and a Jessops 2x all together on my 300 lens mounted on a tripod looking through a double-glazed window. Using the 5x magnification enhancement in Live View I manually focused on a distant tree on the horizon and used a remote release to take the picture.

Compare the following two images. Look carefully in the wide-angle view for the three trees on the hill above the roof heating vent above the white garage door in the centre. The close-up shot using the three stacked converters shows the middle tree full frame.

Admittedly I have not yet tried this "in the field". It was just an experiment to see what the lens was capable of. I was impressed!

Mike
That is impressive Mike, 1680mm through a double glazed window that's heck of a lot of glass.
 
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