1.6x teleconvertor with 100-400mm Canon lens

[RobertCrow]

Asking owners of the new 100-400mm Canon lens, do you ever use a 1.6x teleconvertor or tube extension (anything), to get a lil more out of it sucessfully. I'm planning to buy a Canon 20D, and getting the 100-400mm lens for my wildlife/bird lens. I did learn that with this digital camera theres a 1.6 factor so the lens will be up to 640mm right? Not bad for birds! I was curious if you can also add a smaller 1.6x teleconvertor with good results.
Also, I'm an ol'school slr photagrapher upgrading to digatel, I'm glad to find this forum an u'll be hearing alot more from me lol, ty everyone.

[robertwgross]

Wow. There are several things to get straight here.

First, if you get a 20D, then it has a 1.6 factor in it. We won't get into the details of whether to call it a 1.6 crop factor, or a 1.6 magnification, or any of that.

The 100-400mm L lens fits that fine and works fine.

I am not aware of any 1.6x teleconverter on the market. There are some 1.4x teleconverters. Canon, Sigma, and others make them. The Canon one works fine for such an L lens as this. I've even stacked two teleconverters on the same lens.

However, you can't expect the autofocus to work beyond a certain aperture, with the Canon teleconverter used. So, the combination works fine, within limitations.

When I need to shoot fast with autofocus, I pull off the teleconverters and use the lens. If I need maximum range, then I put on both teleconverters and manually focus the lens. Crude, but effective.

---Bob Gross---

[kfong]

I am not aware of any 1.6x teleconverter on the market. There are some 1.4x teleconverters. Canon, Sigma, and others make them. The Canon one works fine for such an L lens as this. I've even stacked two teleconverters on the same lens.
---Bob Gross---
I have a 1.7X TC made by Promaster. I got it used from Ritz for $25. Mechanical built is quite good, optic quality is so so, but it certainly is good value at 1/20 the price of a Canon TC. It says 1.7X but in reality it is actually 1.6X

Ken

[RobertCrow]

Thanks Robert, Yes I did mean 1.4x for teleconvertor sorry. You say you have stacked 2 1.4x tc's together? Wow. What would the focal length be on like the 20D, I'm curious if you could also tell me the overall focal length of th 100-400 on the 20D with just one 1.4 TC?

I understand to what your saying about taking them off when needing speed to thankyou.
Also, is a Kenco as good to you as a Canon TC?
thanxs

[Turbowolf]

a 100-400 on the 20D is as follows:

with the 1.6 crop factor it equals a 160-640mm for a full-sensor digital/35mm film body.

Add in a 1.4 TC and it equals a 224-896mm for a full-sensor digital/35mm film body.

or do I have this whole crop factor thing wrong????

[Wazza]

900mm would be fun to use. But remember it gets a lot slower with each additional TC, and AF doesn't work too well I heard with 400 + TC.

Anyway 1.6x... I thought that meant the camera weighed that much extra. :p

[kb244]

Crop Factor: This is basically to say the Sensor Size on the camera, is smaller than the 35mm Film area, The lens you use for the camera ( with the exception of the EF-S lens but are still measured the same ) , are meant for 35mm plane. The sensor of the 20D being smaller, there is the crop factor. If you slap on a 300mm lens, The area that is actually covered by the sensor would appear the same as what a 35mm Film camera ( or Full Frame ) would see at 300mm x 1.6.

Its like if you shot a picture with a 300mm lens, cut out the area that the sensor actually covers, perspectivly looks further out. Like digital zoom.

The EF-S lens like say the 18-55, are still measured what they would be on a 35mm camera, but the back element of an EF-S lens, has the excess glass shaved off, so that the back glass only covers the area the Dreb/20D sensor actually takes up.

[RobertCrow]

Thanx for all your input friends!

I've also heard from people that using a 1.4x teleconvertor can effect exposure & color saturation, ect. Is this true.
I guess all I'm really wondering is how well a 1.4x tc would perform on a lense like the 100-400mm.
Oh an thanx for the math, if it worked well on bright days, almost 900mm wow!
That would be wonderful.
I think this would make a good wildlife lens for the 20D on a budget, an a 1.4x tc, would you agree?

[Scottes]

The 1.4TC - any TC - can definitely affect picture quality, but I have many pics with the 100-400 + 1.4TC and they're fine. Not as great as without the TC, but not much worse, and still worthy of printing.

The 100-400 alone is a very good wildlife lens. With the 1.4TC it's certainly longer and that will help at times, but at this point you'll need to manual focus and you'll need time to do that...

[Ikinaa]

One small add-on to the focal length :
The focal length is a property of the lens, not of the film/sensor at the end of it...
So a 50 mm lens for an eos-film camera remains a 50 mm for a eos dslr remains a 50 mm lens for a 6x6cm-film camera...

The focal length of a lens is found by measuring from the optical center of the lens (called the nodal point) to the point where the lens sharply focuses the light rays from a subject located at infinity

[robertwgross]

I have a 1.7X TC made by Promaster. I got it used from Ritz for $25. Mechanical built is quite good, optic quality is so so, but it certainly is good value at 1/20 the price of a Canon TC. It says 1.7X but in reality it is actually 1.6X

"so so" might be generous.

You've just reminded me why I didn't purchase Promaster.

---Bob Gross---

[robertwgross]

Thanks Robert, Yes I did mean 1.4x for teleconvertor sorry. You say you have stacked 2 1.4x tc's together? Wow. What would the focal length be on like the 20D, I'm curious if you could also tell me the overall focal length of th 100-400 on the 20D with just one 1.4 TC?

The math is quite easy.

Also, is a Kenco as good to you as a Canon TC?

The prevailing wisdom is that if you have a really sharp L lens, you'll probably want to use a really sharp 1.4x teleconverter. If you have an ordinary consumer lens, then you'll probably want an ordinary 1.4x teleconverter. Note that the Canon 1.4x teleconverter will not fit most ordinary consumer lenses.

I am aware of Canon, Sigma, and Tamron teleconverters.

This is sort of like buying a race car and then buying high-speed-rated tires. You would not buy a race car and then buy cheap tires for it. By the same token, if you had a junker car, you wouldn't buy the most expensive race tires.

---Bob Gross---

[robertwgross]

I've also heard from people that using a 1.4x teleconvertor can effect exposure & color saturation, ect. Is this true.

For each 1.4x teleconverter, your lens will slow down by one stop. Your camera metering will deal with that, so exposure comes out right, but it is still one stop to deal with. On a bright, sunny day, it is no big deal. On a dim, foggy day, it is kind of a PITA.

I've never heard anything bad said about the Canon 1.4x as far as color goes. I've seen a little color tint in a different one.


I think this would make a good wildlife lens for the 20D on a budget, an a 1.4x tc, would you agree?

Yes and no. It is what I chose last year for a wildlife lens combination. As I stated, you'll probably need to take off all teleconverters to get autofocus, so for a fast-moving animal, that is necessary. For slow-movers, it works fine. There are some animals, like a desert bighorn sheep, that avoid humans. They tend to stay up high in the rocks where it takes serious firepower (long, long lenses) to reach them. But, once they are there, they don't necessarily jump around that much. They tend to stand on a sunny rock. The combination works good for that.

Of course, when you are dealing with those kinds of lens focal lengths with 1.6 factors, you really have to have it on a tripod. You can handhold the lens and shoot, but beware that the IS feature can't make something out of nothing. I've been known to shoot at 100mm or 200mm handheld. When I get it out to 400mm, it becomes awkward to hold with my scrawny arms. At 800mm, the tripod is on full time.

Whether that combination makes sense to you depends on what kind of wildlife you go after.

---Bob Gross---

[RobertCrow]

Thanks alot Bob I have scawny arms too, lol.

Thanks for the info, so seems photographing say like a Great Blue Heron, who spends alotta time standing, would be a nice example of subject using a 1.4x TC with the 100-400, on a nice bright day. Would you agree too that with the 1.6x factor with 20D camera bringing the lens to 160-640mm FL alone be suffecient as far as speed and catchin some good wildlife images?
I was very impressed with some samples I saw in another thread.
Thanks for help.
I'm not a rich man but very passionate about Nature/ wildlife photography as a persanel & wonderful hobby, Just kinda getting started in digatel world and appreciate all your tips.

[gramps]

I wonder how many different explanations of the 1.6 crop factor have been posted in the past 6 months??

[RobertCrow]

I wonder how many times people read the same questions and just simply overlook it an move on,

suggest you do the same.
Lot of people out here just learning an good suggestions are always nice, rather then lame complaints.

I still thank all you for the help in teaching us simple minded folks, lol

[Scottes]

Suggest YOU read the Sticky posts which explain the crop factor 10,000 times. If you need help, help yourself a little first.

[RobertCrow]

Thanks:oops:

[RobertCrow]

WOW!, I'm really sorry, New to forum and didnt realize so much info was packed into those threads.

Thanx for the advice,

[robertwgross]

Thanks for the info, so seems photographing say like a Great Blue Heron, who spends alotta time standing, would be a nice example of subject using a 1.4x TC with the 100-400, on a nice bright day. Would you agree too that with the 1.6x factor with 20D camera bringing the lens to 160-640mm FL alone be suffecient as far as speed and catchin some good wildlife images?

The 1.6 factor in the body certainly helps you on the long end of lens work. Obviously it hurts you on the wide end, but that is not the concern here. I think you will find that lens or that combination to work nicely in bright situations, and you can always pull off the teleconverter when you need that extra stop back.

Last summer I got some good Great Blue Herons that way. In fact, on one, the damned bird just stood there, and I crept up on it very quietly, and I got a head-only shot. When it took off, it seemed like a B-52 bomber overhead.

What kinds of lenses you use depend on too many factors to go into here. If your lenses are too short, then you can always head to the elephant pen at the zoo. By the way, that is an excellent place to try out your new lenses. In general, the animals are not that far away, and they can't escape completely. Go on a quiet day when you can set up your tripod or monopod without crowds around. Pick a sunny day. Just 50 miles from me there is a major zoo that has a free admission day once per month. Guess when I go there?

---Bob Gross---