Teleconverter

ccf15

Senior Member
I have a D3400 with a Sigma (C) 150-600 lens I have been using to photograph a pair of bald eagles at their nest. Federal law says no closer than 330 feet. I am generally 350’ from the nest, but the lake area where they perch/hunt is much further.

My question is can my D3400 & the Sigma handle a 1.5 converter? Or do I need to start thinking about a better camera body?

Thanks,
CC


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Clovishound

Senior Member
Well, the setup you have right now gives you an effective 900mm lens. Keep in mind that if you upgrade to a full frame sensor, you will lose the 1.5 crop factor, and that 600mm will go from effective 900 to 600. I haven't used a teleconverter in several decades, so I can't give you any recent experience. You should make sure that you won't lose AF because your max aperture is too slow. If my math is correct your max aperture with that lens and a 2x converter will give you f13.

FWIW, I recently upgraded from a D3400 to a Z5. I haven't seen that big a difference in image quality between the crop sensor and the full size. They are both right around 24 MP. Perhaps the Z7 with almost double the MPs would have given me a bigger jump, but some of the info I have seen says it's more, but not a lot more. There are other features that have made the switch well worth it, but I was a little disappointed that I didn't get a big bump in rez.
 

BF Hammer

Senior Member
Sigma makes their own 1.4x and 2.0x teleconverters that are compatible with the lens in F-mount. No experience with either the teleconverter or D3400 personally.

But I do have a story of owning a Tamron 1.4x autofocus teleconverter years ago. Was perfectly happy with it on the D80 I was using, but it never worked with the D7000 I bought after. It was included in the trade-in gear I took to the camera store when I bought my D750 so I never tried it with another camera.

Personally my strategy is to use that 24MP resolution of the camera sensor and shoot with a steady base. Shoot RAW + JPG and crop down the RAW image as needed. Eliminate any shake in the images and you will be surprised how much detail will be there with the Sigma lens. A steady tripod and remembering to turn off VC on the lens when using the tripod goes a very long way. And I have some experience photographing eagles in flight with the Sigma 150-600mm C.

I4nbvTb.jpg

And if you don't believe, this is a very extreme crop of Saturn (enlarged from 1:1) using the Sigma. It is a single image with no special astrophotography filters applied. But I used a fast enough shutter speed from a very steady tripod and used a remote shutter release.

IIQLySc.jpeg
 
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hark

Administrator
Staff member
Super Mod
Contributor
It looks like Sigma makes a TC for that lens.

https://www.sigmaphoto.com/150-600mm-contemporary-tc-1401-teleconverter-kit

The problem is the TC will now make the lens a 210-840mm with a variable aperture of f/6.3-9 instead of its usual f/5-6.3. So when you are zoomed out to the long end with the TC, your largest aperture will be f/9. And that's going to cause an auto focus problem.

Nikon has some bodies that will support f/8 as the largest aperture. Those bodies are pretty good with sensing light so they AF okay - albeit sometimes kind of slow. But your body isn't on the list. Will it work? I have no clue. This Nikon article should shed some light on this f/8 feature.

https://www.nikonimgsupport.com/na/NSG_article?articleNo=000028595&configured=1&lang=en_SG

Quote from the Nikon article:

Which DSLR cameras are compatible with focusing at f/8?
Df, D4, D4S, D5, D6, D500, D600, D610, D750, D780, D800, D800E, D810, D850, D7100, D7200, D7500.
 

Needa

Senior Member
Challenge Team
What is it about the teleconverter that causes the issue? I understand the loss of light principal. Assuming the camera has a 5.6 low light autofocus ability does this mean that the f5 – 6.3 lens w/o tele will still have a problem in low light but will work fine on a bright day? Is it simply a matter of the amount of light reaching the AF module? What exactly defines low light?

Any links to good explanations appreciated.
 
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Needa

Senior Member
Challenge Team
There are speed boosters that go the other direction and have .71x for the focal length and you gain a full F stop. These are used to convert a full frame lens to a crop frame sensor body and maintain the full 35mm focal length equivalent.

https://www.bhphotovideo.com/c/prod...54Z3yKT0ZN0ZpiVwxErX12_1SHCglCwwaAgCHEALw_wcB


Thanks. Part of my foggy thinking was not remembering the f number is ratio and not a fixed opening, determined by the focal length to effective aperture.

Link to focal length reducers aka speed boosters.
https://www.alex-stone.com/2020/10/29/busting-speedbooster-myths/
 

ccf15

Senior Member
All -

Thank you for the insight/inputs. I will stick with what I got and work at the editing.

Cheers,
CC


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