Canon 80 D plus 300 F4 with 2x converter: I am puzzled. My Canon 80 D will only give me one (center) fixed focus point with anf4 300 mm prime plus 2x converter ( by my reckoning an...

whitehall Loc: Canada

I am puzzled. My Canon 80 D will only give me one (center) fixed focus point with anf4 300 mm prime plus 2x converter ( by my reckoning an effective f8) yet the camera gives me a 9 point moveable focus group when I put on my 100-400 lens with a 1.4 extender ( with some telephoto applied effectively it is also f8). I guess it is what it is, but if someone could enlighten me, I would certainly appreciate it. Thanks

IGW

robertjerl Loc: Corona, California

whitehall wrote:

I am puzzled. My Canon 80 D will only give me one (center) fixed focus point with anf4 300 mm prime plus 2x converter ( by my reckoning an effective f8) yet the camera gives me a 9 point moveable focus group when I put on my 100-400 lens with a 1.4 extender ( with some telephoto applied effectively it is also f8). I guess it is what it is, but if someone could enlighten me, I would certainly appreciate it. Thanks

IGW

The number of points depends on the extender and lens combo and their circuitry. And the specs I have seen for the 80D show it has 27 f/8 points with the 100-400 mk II and only the center point with the 100-400 mk I when using the 1.4x III. I have used both the 100-400 mk I and mk II on my 7DII with the 1.4x III and I got center point on the mk I and center point expanded with the mk II.

CHG_CANON Loc: the Windy City

Refer to pages 119 - 126 of the 80D User Manual. Your 300 f/4L and 2x extender is a group H combination with AF via only the camera's center point.

crazydaddio Loc: Toronto Ontario Canada

CHG_CANON wrote:

Refer to pages 119 - 126 of the 80D User Manual. Your 300 f/4L and 2x extender is a group H combination with AF via only the camera's center point.

Yep. Good advice.
I checked out all the lenses in the 5Dmkiv manual when I got it.

When you get 3rd party lenses....not all your AF pts are useable...not just extenders impact your AF pts. Something everyone should know as part of your gear decisions.

Suprised I havent seen many posts from UHHers on this topic.

SharpShooter Loc: NorCal

crazydaddio wrote:

Yep. Good advice.
I checked out all the lenses in the 5Dmkiv manual when I got it.

When you get 3rd party lenses....not all your AF pts are useable...not just extenders impact your AF pts. Something everyone should know as part of your gear decisions.

Suprised I havent seen many posts from UHHers on this topic.

Most photographers have no idea what lens groups their lenses fall into.
For example, not all f4 lenses are in the same group.
There's a reason the 400 f2.8 lens is made, and isn't necessarily about low light, but about engaging more focus points and faster more accurate focusing, and yes, in good light!
SS

whitehall Loc: Canada

Thanks. Really helpful. I generally do check prior to buying a lens, but I had this one for some time and only use for lanscape on my 5D mkiv. i was trying to see whether I could strech it on a crop frame.

IGW

IGW

robertjerl Loc: Corona, California

Well on an 80D with the 1.4x you get AOV of a 672 mm and with the 2.0x the AOV is 960 mm.

Is that enough of a stretch for you?
As to the center point only focus, that is what I use most of the time for birds, bugs etc. I also use it for people or close ups of animals (focus on an eye). In fact pretty much everything since I owned 35 mm bodies that had those little center of the screen checkerboard and split focus circles. So I am used to only using the center of the frame for my focus point.

crazydaddio Loc: Toronto Ontario Canada

robertjerl wrote:

Well on an 80D with the 1.4x you get AOV of a 672 ... (show quote)

Confession: only time I DON'T use the center AF if posed portrait at extreme low F setting 1.4 to 2.0 OR BIF overhead....which means about 97% of the time its center AF.

whitehall Loc: Canada

Thanks again.

SharpShooter Loc: NorCal

crazydaddio wrote:

Confession: only time I DON'T use the center AF if posed portrait at extreme low F setting 1.4 to 2.0 OR BIF overhead....which means about 97% of the time its center AF.

Here we go again! Crazy, what does YOUR shooing style have to do with the question posed??
Please elaborate how, how you shoot, helps the OP understand the limitations of his focus dilemma?
SS

robertjerl Loc: Corona, California

SharpShooter wrote:

Here we go again! Crazy, what does YOUR shooing style have to do with the question posed??
Please elaborate how, how you shoot, helps the OP understand the limitations of his focus dilemma?
SS

It tells him that only having a single focus point working doesn't mean he can't photograph as more than a few of us habitually use center point focus anyway.

You will note I mentioned center point focus first.

imagemeister Loc: mid east Florida

whitehall wrote:

I am puzzled. My Canon 80 D will only give me one (center) fixed focus point with anf4 300 mm prime plus 2x converter ( by my reckoning an effective f8) yet the camera gives me a 9 point moveable focus group when I put on my 100-400 lens with a 1.4 extender ( with some telephoto applied effectively it is also f8). I guess it is what it is, but if someone could enlighten me, I would certainly appreciate it. Thanks

IGW

AF at f8 and what KIND of AF - for Canon is very body/lens specific - oh, and ONLY Canon lens and Canon extenders ! - and is rarely mentioned in the reviews !

crazydaddio Loc: Toronto Ontario Canada

SharpShooter wrote:

Here we go again! Crazy, what does YOUR shooing style have to do with the question posed??
Please elaborate how, how you shoot, helps the OP understand the limitations of his focus dilemma?
SS

Hmmm. A bit tangential I will admit...but still related.

Just suggesting that only having a center AF may not be that limiting. Especiallly for long lens photography.

(Some of my other posts in other forumns are much more off topic....I will endeavor to be more careful)

foathog Loc: Greensboro, NC

people who buy off brand lenses don't brag about their shortfalls.

crazydaddio wrote:

Yep. Good advice.
I checked out all the lenses in the 5Dmkiv manual when I got it.

When you get 3rd party lenses....not all your AF pts are useable...not just extenders impact your AF pts. Something everyone should know as part of your gear decisions.

Suprised I havent seen many posts from UHHers on this topic.

dsmeltz Loc: Philadelphia

whitehall wrote:

I am puzzled. My Canon 80 D will only give me one (center) fixed focus point with anf4 300 mm prime plus 2x converter ( by my reckoning an effective f8) yet the camera gives me a 9 point moveable focus group when I put on my 100-400 lens with a 1.4 extender ( with some telephoto applied effectively it is also f8). I guess it is what it is, but if someone could enlighten me, I would certainly appreciate it. Thanks

IGW

5.6 * 1.4 = 7.84. Not 8. I guess the .16 extra gives you the 9 points.