Tele-converter or DX mode

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bleirer said:
I like the quote in big bold letters around 10:15. "All other factors equal - the smaller sensor will have the shallower depth of field."

Good video, worth watching from the beginning. He goes on to explain equivalency and crop factor and why once adjusted by physically moving farther away to fill the sensor with the same size subject the dof increases (because of being farther away). However we have been talking about staying in the same place and by cropping effectively reducing the size of the sensor. At least that's how I see it.
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This is the crux of the confusion/misunderstanding which causes so much discussion on this topic. Many people don't understand the concept of "all things being equal" or the need to compare things at the same FOV and output size.

Edited: forgot to mention output in original post.
 
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NorthernFocus said:
This is the crux of the confusion/misunderstanding which causes so much discussion on this topic. Many people don't understand the concept of "all things being equal" or the need to compare things at the same FOV.
Click to expand...

There are a lot of moving parts. The several photography life articles seemed to explain it very well.
 
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I had a wallhanger shot with a z20mm.
My wife complained about the distance hills are too small, and we should re-capture that scene with a 50mm.

I posted the picture here on BCG, and someone (I forgot who it was) “cropped it” to match the FOV of a 50mm.
Suddenly the distance hills appeared bigger!

Its all eye perception and expectations.

I remember relying on PhotoPills app to calculate DOF for use in our portrait studio. I found the calculations and actual results to be completely wrong!
It was all due to our own expectations in the way we envisioned and perceived the image on screen and on print. Heck, we dared to capture f/1.2. Shots that “looked” great! But according to the app, we had zero DOF…

To answer the question in this topic, TC vs. cropping? It depends!
If I need the light and lower ISO, I would DX. If I need the reach with enough light, I would use a TC.

I think, The lost stop of aperture recorded in the image when using a TC, isn’t right. Why? Because it’s that same amount of light ON THE SUBJECT when DX’ing. And its not like I would stop down the bare lens.

f/6.3 bare lens minus 1 stop = f/9 DOF.
f/6.3 plus a 1.4 TC
OR
f/6.3 bare lens plus DX/crop in post = f/6.3 DOF!
ONLY light and noise are equivalent to f/9.
 
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The two Canon extension tubes arrived yesterday. Weather here was rainy and dull.
Anyway today I did some indoor tests. Initially I was going to use a tripod but tried hand held. The results handheld have convinced me that the stabilization of the Canon 100-400 Mk2 and Canon R7 are combining.

Both of the photographs below are hand held. Distance is 2.5 m.

_H0A6136-DeNoiseAI-standard resize.jpg
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R7 800mm [ 2X Extender ] f11 1/13 Second ISO 1600 Denoised using Topaz AI

_H0A6149-DeNoiseAI-standard resize.jpg
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R7 1120mm [ 2X and 1,4X Extenders ] f11 1/25 Second ISO 12800 Topaz Denoise AI

The data gets confused and is showing 1120mm as 560mm.

Make of this whatever makes you happy.
 
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I'm still trying to understand what is going on. The photo above 1120mm is of an Australian $50 note. [ https://banknotes.rba.gov.au/australias-banknotes/banknotes-in-circulation/fifty-dollar/ ] I have been playing with the image. This is a crop:

test $50 PP3 04 07 24- resize.jpg
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My calculations suggest a diagonal field of view of about 0.4 degrees.
Adding an Extender seems to me to not only have the optical effect of the Extender but also acts as an Extension Tube.
All of this thinking is making my brain hurt. Hopefully the weather will clear up today.
 
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Robert S said:
Adding an Extender seems to me to not only have the optical effect of the Extender but also acts as an Extension Tube.
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You might want to start a new thread on macro extension tubes as it's a different discussion than teleconverters vs cropping.

But FWIW, if by 'extender' vs extension tube you mean teleconverter vs extension tube a teleconverter does not change the minimum focusing distance of a lens but an extension tube does. You can of course stack extension tubes and teleconverters to get even closer to a subject for greater magnification but a TC by itself doesn't change the minimum focusing distance but it does increase the effective focal length so you get greater magnification by having the original minimum focusing distance but with a longer focal length lens.
 
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DRwyoming said:
You might want to start a new thread on macro extension tubes as it's a different discussion than teleconverters vs cropping.

But FWIW, if by 'extender' vs extension tube you mean teleconverter vs extension tube a teleconverter does not change the minimum focusing distance of a lens but an extension tube does. You can of course stack extension tubes and teleconverters to get even closer to a subject for greater magnification but a TC by itself doesn't change the minimum focusing distance but it does increase the effective focal length so you get greater magnification by having the original minimum focusing distance but with a longer focal length lens.
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Thanks Dave. I might put it all in the too hard basket. Every time I think I am getting it sorted I find another tangent to fly off on.
The last photo I posted was obtained using two teleconverters [ extenders ] and one extension tube. Needed the extension tube to stack the teleconverters.
 
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Robert S said:
Thanks Dave. I might put it all in the too hard basket. Every time I think I am getting it sorted I find another tangent to fly off on.
The last photo I posted was obtained using two teleconverters [ extenders ] and one extension tube. Needed the extension tube to stack the teleconverters.
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Yup, if you add the tube to couple a pair of TCs then yup the minimum focusing distance drops a bit. Basically anytime you add a tube (or bellows) that has no optical elements (no glass) you'll lower the minimum focusing distance but also lose the ability to focus the lens at infinity focus. When you only add a TC which has optical elements you increase the effective focal length of the lens but don't change its minimum or maximum focusing distances.

How much you impact the minimum and maximum focusing distances when adding extension depends on the length of the extension and the focal length of the lens or lens + TC combo that sits out in front of the extension tube. When you add combos of both TCs (one or more) and extension tubes (one or more) then the length of the tubes and where they sit in the lens-TC chain as well as the focal length of the lens itself changes how much the minimum and maximum focusing distances change. IOW the order of things matters when you start stacking multiple systems.
 
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Similar here.
Generally spoken TC's have their terrain where they provide clear benefits against cropping (Steve's video about TC's was already mentionned earlier).
As I don't have a fast Z tele yet, I didn't buy a Z TC simply because both my Z 100-400 as well as the Z 180-600 don't really like TC's and additionally with the TC on the 180-600 you end up at f9 at the long end which doesn't make much sense to me.
That said, if you keep an eye on noise level, cropping might not as bad as many think. Shooting a Z8 in DX still gives you a resolution that is pretty close to what the latest pro bodies in DSLR times (D5/D6) provided full frame.
 
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He shows a good example of what I was talking about if you read down into this article. One shot at 24mm the other at 500mm but the subject fills the same frame. He tells us the dof is the same, but the background looks better because being farther away makes the background blur bigger relative to the subject size.

photographylife.com

Depth of Field in Wildlife Photography

photographylife.com photographylife.com
 
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