Somtimes overlooked benefit of TC's

[Lance B]

It is sometimes overlooked, but another benefit of a TC is the close focus ability it permits a lens +TC combo when compared to a lens with the same focal length that has no TC attached.

Usually, a prime lens (non macro) has a close focus of about 8-10x it's focal length for the shorter tele's and maybe 6-10x focal length for longer tele's. This is a little Nikoncentric as I shoot Nikon, but the same applies to basically all DSLR's. If we look at Nikons prime lenses (and this is pretty much the same for all manufacturers lenses), a 50mm lens for example usually has a close focus of about 45-50cms, an 85mm is about 75-85cm, a 300 is about 230cm(AF) 220cm(MF), a 600mm is about 480cm(MF) and 500cm(AF).

However, if you use a 300mm f2.8 VRII and add the 2x TCIII, you have a 600mm lens that can focus down to what the 300 can focus to of 220cms but obstensibly with the magnification of the 600mm lens due to the TC, therefore doubling the recorded size of your subject matter compared to a bare 300 or a normal 600.

I do find it an annoyance in many situations that primes generally only focus down to this 8-10x their focal length for shorter tele lenses and 6-10x at the longer teles, especially lenses like the 85mm f1.4G, which can limit it's use. I do like the idea of Zeiss's 100 f2 Makro Planar which is more like a close focus 100mm prime than a macro lens.

Anyway, you can use a TC on some of these lenses to get a much better close focus ability. The benefit can be abserved when trying to shoot very small birds like wrens, pardalotes etc where a normal prime may not allow close enough focus for the bird to fill the frame and therefore a TC can help.

Here are some quick test shots of the Nikon 300 f2.8 VRII + 2x TCIII on my D7000 all taken at focus distances of about 2.5mts or thereabouts. All using a monopod as support. Bearing in mind that some were taken at f8 and at this close range the DOF is only about 4mm!! It makes basically no difference if I had used a macro lens as the DOF at that distance with the same magnification and aperture results in simlar DOF.

Focal Length 600 mm
Exposure Time 1/250 sec
Aperture f/10
ISO Equivalent 400

http://www.pbase.com/lance_b/image/137371122/original.jpg

Focal Length 600 mm
Exposure Time 1/100 sec
Aperture f/8
ISO Equivalent 400

http://www.pbase.com/lance_b/image/137371124/original.jpg

Crop of above:

http://www.pbase.com/lance_b/image/137371551/original.jpg

Focal Length 600 mm
Exposure Time 1/100 sec
Aperture f/8
ISO Equivalent 400

http://www.pbase.com/lance_b/image/137371125/original.jpg

Focal Length 600 mm
Exposure Time 1/400 sec
Aperture f/11
ISO Equivalent 400

http://www.pbase.com/lance_b/image/137371127/original.jpg

Focal Length 600 mm
Exposure Time 1/125 sec
Aperture f/11
ISO Equivalent 400

http://www.pbase.com/lance_b/image/137371128/original.jpg

[salnel]

This is really interesting info,Lance..I didn't realise that I could focus so close with a telephoto lens! Excellent photos, especially the hibiscus..the detail is terrific! (By the way...LOVE this lens:D)

[Lance B]

This is really interesting info,Lance..I didn't realise that I could focus so close with a telephoto lens!

Actually, your 300mm f4 lens is rather an exception to the rule as it can focus down to 1.45mts which is half the usual minimum focus distance of a prime lens of that length! My 300mm f2.8 VRII (which took these photos) has a normal minimum focus distance of 2.3mts in AF and 2.2mts if I manually focus. So, you can see that yours focuses much closer. With a 2x TC attached it will mean that your magnification will be enourmous! In fact, I would say that you are almost getting to macro type magnifications, so a tripod would be required.

Just remember that if you do get a 2x TCIII for your lens that it will slow the AF down considerably and that your minimu shutter speed will need to be 1/focal length (+ 2x TC) x 1.5 = 1/600x1.5= 1/900sec for reasonably successful handholdability. A tripod, or at least a monpod, is the order of the day! A 1.4x TCII is where you should start out at.


Excellent photos, especially the hibiscus..the detail is terrific! (By the way...LOVE this lens:D)

Great to her, Sally! :)

Thank you for your very nice comments, too!

[salnel]

My 1.4 TC turned up so I am going out this arvo to have another go at some poor birds! I have a monopod and used that yesterday and really enjoyed it. Would you recommend the 2x TC111 for this lens or would it make it too slow?

[Wayne]

Would you recommend the 2x TC111 for this lens or would it make it too slow?

Short answer is no.

Widest aperture available would be f/8 and that would mean your shutter speed will be very slow alot of the time with anything other than very bright scenes, not to mention you will be using manual focus exclusively as f/8 is beyond the point AF will work on that lens.

[salnel]

Thanks,Wayne..I thought it wasn't right...happy with what I have:)

[Lance B]

My 1.4 TC turned up so I am going out this arvo to have another go at some poor birds! I have a monopod and used that yesterday and really enjoyed it. Would you recommend the 2x TC111 for this lens or would it make it too slow?

I have used the 2x TCIII on the 300 f4 and the results are excellent, but it can slow down the AF considerably in low light. However, it did AF in good light. Samples:

http://www.pbase.com/lance_b/image/136169669/original.jpg

Crop of above:

http://www.pbase.com/lance_b/image/136169671/original.jpg

http://www.pbase.com/lance_b/image/136169677/original.jpg

Crop of above:

http://www.pbase.com/lance_b/image/136169679/original.jpg

[jim]

She's a lovely young lady, but will she thank you for showing off her nose in that much detail?

[salnel]

Thanks, Lance...this is a whole new world (love the dog:th3:).

[OzzieTraveller]

G'day Lance

Agree with your comments - well thought out "tute" - thanks

Regards, Phil

[reaction]

does this apply to macro too?
as a Nikon shooter we only have 1:1 access w/o bellows while Canon has that 1:5 lens

[Lance B]

does this apply to macro too?
as a Nikon shooter we only have 1:1 access w/o bellows while Canon has that 1:5 lens

Yes, it would. A 2x TC should mean that your subject is twice as big as without the TC disregarding any focus shift issues with regards to focal length, ie focal length generally shortens the closer the focus distance. Focal length of a lens is measured at infinity focus.

[reaction]

Hmm, may be an idea, except I saw the price of a 2x!

[Lance B]

Hmm, may be an idea, except I saw the price of a 2x!

Trust me, It's worth it!