How bad is a 2x teleconverter on f/4 telezoom?

Started 6 months ago | Polls
Jocksa
Jocksa Senior Member • Posts: 1,098
How bad is a 2x teleconverter on f/4 telezoom?
1

Having never used a teleconverter on anything slower than f/2.8 lenses, I decided to try it on my 70-200 f/4 telezoom just to see how bad it was.

Here are two shots: one at 200mm with no TC, one at 100mm with a 2x TC.

I was surprised how close they were. I accept that f/8 isn't ideal for low light conditions and my camera only has a few f/8 autofocus sensors. But for the number for times I need focal lengths over 200mm, a TC is a lot lighter to carry than another lens provided the quality is OK.

Given all we know about teleconverters, zooms and slow apertures, can you tell which is which?

Picture 1

Picture 2

 Jocksa's gear list:Jocksa's gear list
Nikon D850 Nikon AF-S Nikkor 70-200mm F4G ED VR Nikkor AF-S 300mm f/4E PF ED VR Nikon AF-S Teleconverter TC-14E III Nikon AF-S Teleconverter TC-17E II +3 more
POLL
Picture 1 is WITH teleconverter
75% 3  votes
Picture 2 is WITH teleconverter
25% 1  vote
  Show results
sybersitizen Forum Pro • Posts: 19,882
Re: How bad is a 2x teleconverter on f/4 telezoom?
1

Jocksa wrote:

... can you tell which is which?

I can tell that #1 is much sharper than #2.

Smaug01
MOD Smaug01 Veteran Member • Posts: 5,367
Agreed; #1 is native
1

Either that, or your lens is a LOT better at 100 than 200 mm.

Thanks for illustrating that sometimes "good enough" is not A Bad Thing.

-- hide signature --

-Jeremy
*********
"Rudeness is the weak man's imitation of strength."
-Eric Hoffer
Opinions expressed are mine and not necessarily DPR's

 Smaug01's gear list:Smaug01's gear list
Panasonic Lumix DMC-TS30 Pentax MX-1 Panasonic FZ1000 Olympus OM-D E-M10 III Nikon D610 +33 more
bobn2
bobn2 Forum Pro • Posts: 68,625
Re: How bad is a 2x teleconverter on f/4 telezoom?
2

Jocksa wrote:

Having never used a teleconverter on anything slower than f/2.8 lenses, I decided to try it on my 70-200 f/4 telezoom just to see how bad it was.

Here are two shots: one at 200mm with no TC, one at 100mm with a 2x TC.

I was surprised how close they were. I accept that f/8 isn't ideal for low light conditions and my camera only has a few f/8 autofocus sensors. But for the number for times I need focal lengths over 200mm, a TC is a lot lighter to carry than another lens provided the quality is OK.

Given all we know about teleconverters, zooms and slow apertures, can you tell which is which?

Picture 1

Picture 2

There's a lot of misunderstandings about TCs. First is that a TC degrades the image. A good one doesn't so much, but it does magnify the image, so the lens' lp/mm gets divided by the TC ratio (except for a 'matched multiplier', which uses some of its elements to add additional correction to the lens). Then there are zoom lenses, mostly but not invariably, they are worst at their long end.

-- hide signature --

Is it always wrong
for one to have the hots for
Comrade Kim Yo Jong?

BSiler Contributing Member • Posts: 561
Re: How bad is a 2x teleconverter on f/4 telezoom?

Interesting comparison.  I guess the longer exposure was also a clue to which image was shot with the TC.

 BSiler's gear list:BSiler's gear list
Nikon Z7 II Nikon AF-S Micro-Nikkor 105mm F2.8G IF-ED VR Nikon AF-S Teleconverter TC-14E III Nikon Z 24-70mm F4 Nikon 500mm F5.6E PF +2 more
Lensmate
Lensmate Veteran Member • Posts: 5,416
Re: How bad is a 2x teleconverter on f/4 telezoom?
1

Jocksa wrote:

Having never used a teleconverter on anything slower than f/2.8 lenses, I decided to try it on my 70-200 f/4 telezoom just to see how bad it was.

Here are two shots: one at 200mm with no TC, one at 100mm with a 2x TC.

I was surprised how close they were. I accept that f/8 isn't ideal for low light conditions and my camera only has a few f/8 autofocus sensors. But for the number for times I need focal lengths over 200mm, a TC is a lot lighter to carry than another lens provided the quality is OK.

Given all we know about teleconverters, zooms and slow apertures, can you tell which is which?

TC's [good ones] are best used with prime lenses.

-Martin P

 Lensmate's gear list:Lensmate's gear list
Sony RX100 Sony RX100 VII Sony Cyber-shot DSC-F717 Sony a99 II Sony Alpha DSLR-A100 +11 more
FrancoD Forum Pro • Posts: 14,704
Re: How bad is a 2x teleconverter on f/4 telezoom?

N1 is MUCH sharper when enlarged.

Doug Haag Senior Member • Posts: 2,454
Re: How bad is a 2x teleconverter on f/4 telezoom?

I don't use a teleconverter.  But I ran into this video that is relevant to the topic just the other day.

https://www.youtube.com/watch?v=p08yUEFIRGE

Jocksa
OP Jocksa Senior Member • Posts: 1,098
Re: #1 is native - No, #1 is the teleconverter!

Smaug01 wrote:

Either that, or your lens is a LOT better at 100 than 200 mm.

Thanks for illustrating that sometimes "good enough" is not A Bad Thing.

No and yes.

Picture number 1 is with the teleconverter. The only explanation that I can see is that the lens is better at 100mm than 200mm, which is often the case.

In the interest of full disclosure, here are another couple of shots taken with the TC at longer settings.

135mm x2

200mm x 2

The 200mm x2 shot is the softest of the 4. BUT it's sharper, even in the corners, than some lenses I've owned (17-55/2.8 DX for example), and bearing in mind that this is the bogeyman combination of slow, zoom lens and 2x converter, I think it's useable and I didn't expect it to be when I set out.

-- hide signature --

“Stand in front of something more interesting.”

 Jocksa's gear list:Jocksa's gear list
Nikon D850 Nikon AF-S Nikkor 70-200mm F4G ED VR Nikkor AF-S 300mm f/4E PF ED VR Nikon AF-S Teleconverter TC-14E III Nikon AF-S Teleconverter TC-17E II +3 more
JustUs7 Senior Member • Posts: 2,131
Re: #1 is native - No, #1 is the teleconverter!

Before I got this far, I voted #1 as teleconverter. What do I win?

I just looked in thread on my phone. It looked a little darker to me. That’s why I voted that way.

But with my extensive analysis and experience, you may as well have asked, “Did it come up heads or tails?”   My odds of getting it right would have been equal. 😁

 JustUs7's gear list:JustUs7's gear list
Canon EOS RP Canon EOS Rebel SL1 Canon EOS 1000D Canon EOS M6 II Canon RF 24-240mm F4-6.3 +7 more
FrancoD Forum Pro • Posts: 14,704
Re: #1 is native - No, #1 is the teleconverter!

The shot taken at 135mm + 2x is still sharper enlarged (cropped) to the same size as the one taken at 200mm plus 2x, indicating that indeed your lens is softer at 200mm.

I think that is the biggest problem many have with even the better 2x and that is we want to use it at the top end when in fact the top end is often the worst .

So maybe rather than ,say , using a 2x at the 600mm end of one of those 150-600mm, it would work better at , say , 500mm even if you still need to crop at that.

Jocksa
OP Jocksa Senior Member • Posts: 1,098
Re: #1 is native - No, #1 is the teleconverter!

FrancoD wrote:

So maybe rather than ,say , using a 2x at the 600mm end of one of those 150-600mm, it would work better at , say , 500mm even if you still need to crop at that.

I think this is right if sharpness is your priority but convenience and weight are factors I also value. What my crude tests have shown me so far is that in good light, I've nothing to fear from putting my humble 70-200/4 on the TC if that's the only way to get the shot.

-- hide signature --

“Stand in front of something more interesting.”

 Jocksa's gear list:Jocksa's gear list
Nikon D850 Nikon AF-S Nikkor 70-200mm F4G ED VR Nikkor AF-S 300mm f/4E PF ED VR Nikon AF-S Teleconverter TC-14E III Nikon AF-S Teleconverter TC-17E II +3 more
Jocksa
OP Jocksa Senior Member • Posts: 1,098
Teleconverter vs cropping

So the other obvious option is to shoot at 200mm and then crop to the equivalent field of view of 400mm. This is taken on a D810 which has pixels to spare, so the result would probably be worse on something like a 21MP D500.

Using the native 200mm shot cropped and upsampled and the 200mm with teleconverter the centres look like this,

Crop centre

Teleconverter centre

and the corners like this,

Crop corner

Teleconverter corner

-- hide signature --

“Stand in front of something more interesting.”

 Jocksa's gear list:Jocksa's gear list
Nikon D850 Nikon AF-S Nikkor 70-200mm F4G ED VR Nikkor AF-S 300mm f/4E PF ED VR Nikon AF-S Teleconverter TC-14E III Nikon AF-S Teleconverter TC-17E II +3 more
sybersitizen Forum Pro • Posts: 19,882
I only said it's sharper

Smaug01 wrote:

sybersitizen wrote:

Jocksa wrote:

... can you tell which is which?

I can tell that #1 is much sharper than #2.

Agreed; #1 is native

I didn't say #1 is native. I only said it's sharper.

Jocksa
OP Jocksa Senior Member • Posts: 1,098
Re: I only said it's sharper

sybersitizen wrote:

Smaug01 wrote:

sybersitizen wrote:

Jocksa wrote:

... can you tell which is which?

I can tell that #1 is much sharper than #2.

Agreed; #1 is native

I didn't say #1 is native. I only said it's sharper.

Which, of course, wasn’t the question.

-- hide signature --

“Stand in front of something more interesting.”

 Jocksa's gear list:Jocksa's gear list
Nikon D850 Nikon AF-S Nikkor 70-200mm F4G ED VR Nikkor AF-S 300mm f/4E PF ED VR Nikon AF-S Teleconverter TC-14E III Nikon AF-S Teleconverter TC-17E II +3 more
FrancoD Forum Pro • Posts: 14,704
Re: Teleconverter vs cropping

That was the next suggestion I was going to make. In your case it looks like the 2x is working , with other combinations cropping works better . In the film days because most could not afford pro printing so cropping wasn't all that easy, 2x were more useful to most than they are now. But again, each specific combination can give different results so one needs to test to find out . (including of course possible copy to copy differences. As in my particular 80-200mm could be softer or sharper than the next one)

sybersitizen Forum Pro • Posts: 19,882
Re: I only said it's sharper

Jocksa wrote:

sybersitizen wrote:

Smaug01 wrote:

sybersitizen wrote:

Jocksa wrote:

... can you tell which is which?

I can tell that #1 is much sharper than #2.

Agreed; #1 is native

I didn't say #1 is native. I only said it's sharper.

Which, of course, wasn’t the question.

Nonetheless, it was the answer I gave. I don't want someone 'agreeing' with something I did not say.

Keyboard shortcuts:
FForum MMy threads