topic Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's in EF & RF Lenses

Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Sun, 10 Sep 2017 15:21:25 GMT

I have focus problem with my newly acquired 600mm IS series 2 canon lens.

I have a 60d, a 7d mk2 and a 5d mk3The lens works well on all three cameras, if I couple it up to a 1.4 iii or 2.0 iii tc, the focus goes to pot (see image, AF point bang in the middle of the birds back.) The bird was approx. 200 ft away.

If I couple it up to the 1.4 on my 60d I get fantastic images even at about 2KM distance.

Any one had any similar problems. I would be grateful for any info. Thanks in advance.

Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Sun, 10 Sep 2017 15:22:43 GMT

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Waddizzle — Sun, 10 Sep 2017 19:27:25 GMT

@Carlosbuddie wrote:
I have focus problem with my newly acquired 600mm IS series 2 canon lens.
I have a 60d, a 7d mk2 and a 5d mk3The lens works well on all three cameras, if I couple it up to a 1.4 iii or 2.0 iii tc, the focus goes to pot (see image, AF point bang in the middle of the birds back.) The bird was approx. 200 ft away.
If I couple it up to the 1.4 on my 60d I get fantastic images even at about 2KM distance.
Any one had any similar problems. I would be grateful for any info. Thanks in advance.

First you say it doesn't work with a telecovnverter, and then you say it does work. Problem solved. BTW, what brand of TC?

What is the f/stop of your lens? That is the most significant specification that determines how well a given lens might work with a given combination of lens and body. A teleconverter raises the effective minimum f/stop of lens. A 1.4 converter rail rise the minimum f/stop by one full stop, and a 2.0 converter will raise the minimum f/stop by two full stops.

The increase in f/stop is the price that you pay for the increase in effective focal length. Every AF sensor has photo sensors that require a certain minimum amount of light to function accurately and consistently. In other words, if the minimum aperture of a lens is too high, then the camera firmware will disable the AF system, when you focus through the viewfinder. Live View uses a different focus system.

Most Canon DSLRs cannot consistently and accurately focus with a lens that has a minimum effective aperture smaller than f/5.6. Your 60D falls into this category. Canon's professional grade cameras have sensors that focus down to f/8, but this ability is limited to just the center focus point.

When you used the teleconverter, you may have noticed a change in the number of available AF points. With the 7D and 5D camera bodies, you should have only been able to use just the center point in AI Servo mode. In One Shot mode, depending upon your settings, you should be able to get the center and a few surrounding points, but only the center locks focus. With the 60D, the camera should not have been able to AF though the viewfinder, at all.

There is nothing that I saying is secret knowledge. All of it is in the documentation of your gear.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Sun, 10 Sep 2017 20:25:35 GMT

Thanks for your reply but I think you have misread my post.

I said the lens works on all 3 bodies until I attach the tc's, Which by the way are both Canon series 3.

When I attach the tc's to the 7d and the 5d although the image in the viewfinder is clear, the actual image in the camera is out of focus. Incidfentally using manual focus makes no difference.

When I attach the 1.4 tc to my 60 d everything works perfectly, obviously the 2x tc will not focus as the minimum aperture is to big.

The lens as I am sure you know is minimum aperture of f4, therefore the 60d will AF

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Waddizzle — Sun, 10 Sep 2017 21:51:12 GMT

@Carlosbuddie wrote:
Thanks for your reply but I think you have misread my post.
I said the lens works on all 3 bodies until I attach the tc's, Which by the way are both Canon series 3.
When I attach the tc's to the 7d and the 5d although the image in the viewfinder is clear, the actual image in the camera is out of focus. Incidfentally using manual focus makes no difference.
When I attach the 1.4 tc to my 60 d everything works perfectly, obviously the 2x tc will not focus as the minimum aperture is to big.
The lens as I am sure you know is minimum aperture of f4, therefore the 60d will AF

"I have a 60d, a 7d mk2 and a 5d mk3The lens works well on all three cameras, if I couple it up to a 1.4 Â Â iii or 2.0 iii Â tc, the focus goes to pot."

"If I couple it up to the 1.4 on my 60d I get Â fantastic images even at about 2KM distance."

Nope, I didn't misread your post. At first it didn't work with the 60D. Now? It works great with you 60D. But, it should work with all of the camera bodies, though.

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Comparinng the image in the viewfinder to "the actual image in the camera" can be misleading because of the diopter. Is it in focus in Llive View? In fact, all of the cameras should be able to focus in Live View mode, even if the effective minimum aperture is over f/8.

It could be some combination of AF settings and initial AF point selection in the newer bodies. Make sure you always start with the center AF point, especially with the 2.0x extender. Make sure that you have the latest firmware. Check to see if it works in Green [A] mode, too.

If it still doesn't work with the newer bodies, then contact Canon Support.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

ebiggs1 — Sun, 10 Sep 2017 23:44:07 GMT

You have this lens, Canon EF 600mm f/4L IS II USM Lens? A $12,000 dollar lens. I have one and I am probably the only regular here that has ever used one. Mine is the first version.

All your cameras except the 6D should AF with either a 1.4x or 2x t-con. However, just because it will does not mean much because there is so much more to using a focal length of 1200mm at f8.

"I get fantastic images even at about 2KM distance."

I am guessing '2km' means 2 kilometers? OK, at that distance you add an additional problem. The atmosphere. That's right just the air itself causes issues. A big misconception about super teles is they were designed to photograph things a long ways away. Yeah they will but actually they shine at filling the shot with tiny subjects at much closer distances. A small bird for example at 25 to 30 feet. Or, perhaps the face of a baseball or football player. 100 yards or less.

My best advice for you is two things. One, get closer, get much closer. Two, get a real beefy tripod. 1200mm at f8 is not a hand hold lens.

Oh, yeah, one more thing forget using the 2x t-con all together. Even better stop using the 1.4x too!

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Mr_Fusion — Mon, 11 Sep 2017 05:05:57 GMT

I have two guesses and a point here.

1) Camera shake. Either your tripod isn't strong enough to hold that weight. Also, a lens that size will catch a lot of wind. Remember, with a lens that long, any movement is amplified a heck of a lot.

Use the most robust tripod you can buy. You are using a serious, heavy duty lens, use a serious, heavy duty tripod.

Second would be to also use a remote shutter. That way you aren't even breathing on the camera when you take the picture.

2) Atmospheric disturbance. This is a real problem in long range sharp shooting. As the sun heats the ground, the air rises, causing a shimmering effect. Moisture in the air can also cause disturbances. While we can see this happen over long distances of flat terrain, it also happens over undulating and shorter terrain too.

In the viewfinder trhe image appears clear and in focus because our eyes compensate for minor deviations. The shot though, captures a view faster than our eyes would notice.

3) Have you tried those teleconverters on shorter lenses, say a 200? That would tell you how much distortion they bring to the issue. We know they will bring some distorsion, the question is how much.

As I said, I'm guessing, but I would be interested in any other explanation.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 11:55:55 GMT

Thank you for your reply

I mentioned the 2KM image because I can't understand why a 6 year old 60d with 600m lens and 1.4 converter wil focus perfectly at that didtsnce but a 7d mk2 and 5dmk3 both less than a year old, cannot focus with either of the converters at a distance of 200 ft. Incidentally A Tripod was used on all shots plus IS was switched on.

I understand also about the atmospheric distortion, we have temperatures regularly 35 -40 c. I wouldn't normally use the lens for anything at that distance I just wanted to see how all the cameras and lens +tc's performed taking the same shot. The 60d wasthe only on that could give me an acceptable result.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 11:56:47 GMT

Thank you for your reply

I understand also about the atmospheric distortion, we have temperatures regularly 35 to 40 c. I wouldn't normally use the lens for anything at that distance I just wanted to see how all the cameras and lens +tc's performed taking the same shot. The 60d was the only on that could give me an acceptable result.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

RobertTheFat — Mon, 11 Sep 2017 12:19:32 GMT

@Carlosbuddie wrote:
Thank you for your reply
I mentioned the 2KM image because I can't understand why a 6 year old 60d with 600m lens and 1.4 converter wil focus perfectly at that didtsnce but a 7d mk2 and 5dmk3 both less than a year old, cannot focus with either of the converters at a distance of 200 ft. Incidentally A Tripod was used on all shots plus IS was switched on.
I understand also about the atmospheric distortion, we have temperatures regularly 35 -40 c. I wouldn't normally use the lens for anything at that distance I just wanted to see how all the cameras and lens +tc's performed taking the same shot. The 60d wasthe only on that could give me an acceptable result.

Given the reported symptoms, the first thing I'd do is see if the lens needs autofocus microadjustment on the 5D3 and the 7D2. I've yet to encounter an "L" lens that needed AFMA on any of my cameras; but with a lens that long and a TC added, you're arguably putting some major stress on the cameras' AF systems. If that turned out to be the problem, you'd be in luck, because the 60D is the only one of your cameras that doesn't have AFMA.

Another thing you might try is to turn off IS. Some people claim that IS can do more harm than good when the camera's on a tripod. I don't know whether it's true, but the experiment can't do any harm.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 12:39:15 GMT

Hi Bob,

Tried all that, I have tried just about any and every combintaion of anything I could think of all to no avail. 😞

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

ebiggs1 — Mon, 11 Sep 2017 14:20:28 GMT

The obvious question, does the lens/camera combo work as expected with out the t-cons? Remember you are getting simple photographic logic when you ask people that have never used a lens in this category. I know my lens works very well on a 7D and 1D Mk IV and Ds Mk III. But I don't use any t-cons. BTW, what brand T-con are you tying to use?

A lens of this type can benefit form a C&C from time ot time. Send it to Canon for a C&C and they will go over it completely. Lenses in this range are unto themselves. They are not and do not act like the more common and used standard lenses.

My Sigma 150-600mm S works well at 600mm on these cameras, too.

Most likely the reason your 6D focuses at 2KM is the DOF is huge at that distance. So, if it missed by 10 or 20 feet, no biggie.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

TCampbell — Mon, 11 Sep 2017 15:22:26 GMT

Whenever you question the accuracy of camera & lens focus, you really can't come to any conclusions unless you do what I'd consider to be somewhat scientifically valid testing procedures.

In other words you have to think of all the things that can go wrong which would be attributed to factors OTHER than the camera & lens.

1) Was the camera on a SOLID tripod? I did read that you had a tripod... but was it a beefy tripod?

2) Was it windy?

3) What was the shutter speed? Did you use mirror lock-up mode?

4) Was the subject moving?

5) Did you use a remote release or self-timer to take the shot?

6) Was it hot (at a distance of 2km, thermals radiating off of hot earth will distort the image.)?

We could come up with more reasons... these are just a few examples.

You might want to do some testing where you can control these conditions... I would encourage you to use an actual focus-accuracy target such as a "LensAlign" or "LensCal". These tools offer a high-contrast target on a flat card.... but that's adjacent to a sloped scale with high-contrast on it as well. The idea is you focus on the target but then check the sloped scale to see if some point along that scale has better focus than the target (it tells you if your camera & lens are front-focusing or back-focusing.)

The fact that the 60D is able to achieve a nice image says that there's nothing wrong with the "optics" per se. But your 7D II or 5D III might need to do an auto-focus micro-adjust (and you want a test target to work that out.)

It's actually encouraging to hear that the 60D is doing well with the lens & teleconverter combo because it suggests that the lens doesn't need service. We just need to work out why you're not getting similar good results with your 7D II or 5D III.

What's interesting is that the 60D is the only xxD series body that does NOT support auto-focus micro-adjustments (AFMA) and that's the one that you're happy with. The other cameras that you aren't happy with are the ones that let you adjust the focus.

When the phase-detect auto-focus system is working, light enters the camera, bounces off the secondary mirror and down into the focus sensors. The sensors have a beam-splitter (a prism) that splits the light into two paths that will exactly re-converge ONLY if the subject is in focus. But if not focused they will be out-of-phase. The computer can detect how far out-of-phase they area and in which direction. It computes how much of a focus adjustment is required and then it moves to to the correct focus point. The amount of focus adjustment is actually computed and the lens is ordered to focus. The amount of adjustment will be different with just the lens alone vs. the lens coupled with a teleconverter (but the firmware knows this).

If the camera isn't nailing the focus, you can use a test target to work out how much of a correction is needed and both the 7D II and 5D III will let you program in some amount of adjustment (the cameras can "remember" something like 50 unique lenses. So the focus adjustment for THIS lens might not be the same as the focus adjustment for your other lenses.)

I'm not say that your camera & lens combo do need a focus adjustment (AFMA) ... but I am saying it's certainly a possibility (and maybe even a very strong possibility). This is something you can do yourself -- no need to send the equipment to Canon for service.

When using a long, heavy camera lens to shoot moving subjects, you might want to consider a beefy tripod base with a gimbal head (the Wimberley gimbal heads are popular. I own an Induro head which is basically the same as a Wimberley head). The gimbal head allows you balance the the camera & lens such that it is neutrally balanced in all directions. Because of this, you can point the camera anywhere and there's actually need to snug down the tripod head. The camera will remain pointed where you put it. This allows you to move the camera "like a tail-gunner" to capture any targets. If you tried this with a ball-head or pan-head, you'd have to keep re-snugging the head.

BTW, for many lenses, the image stabilization should be disabled if the lens is attached to a tripod. This is because the snap motion to adjust the optics in the IS system can actually cause a vibration which is interally felt (when on a tripod) and the lens will attempt to react to it's own vibration. It results in a feedback loop. But newer lenses (and I think the 600 is new enough) can detect when this is happening. For those newer lenses you can leave the IS on.

If the 60D can get a sharp image then it's possible to get a sharp image with the other cameras. The lens is basically like a movie projector attemping to shine an image on a movie screen. If it can be sharp on the 60D then it can be sharp on the others as well.

You can only trust manual focus via the viewfinder if you've adjusted your viewfinder for your own eyes. To do this, deliberately de-focus the lens and point it at a plain white wall (or plain blue sky - but not near the sun). Carefully adjust the diopter wheel (on the corner of the viewfinder) until the viewfinder graphics are as sharp as possible.

The camera is basically projecting an image onto the viewfinder's focus screen. It's the frosted "glass" you see above the mirror in your camera. When you look through the viewfinder, you are inspecting the image on that focus screen. But depending on your eyes, whether or not you use glasses, etc. that screen may not be in perfect focus to YOUR eyes even if the image on the screen is perfectly sharp. The diopter adjustment wheel allows you to adjust for that to compensate for your eyes. Once the graphics you can see on the focus screen (focus points, grid lines, etc.) are perfectly sharp you can now trust manual focus.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

ebiggs1 — Mon, 11 Sep 2017 16:18:32 GMT

About IS, my thoughts.

Do not turn IS on unless working at shutter speeds lower than inverse of the focal length of the lens. It can hurt the sharpness a little. (600mm = SS 1/600 or rounded to 1/1000)
If you decide to turn IS on, make sure to half-press the shutter button for a second to let the camera/lens stabilize a little first. If you shoot right away without stabilizing, it will most likely negatively impact the sharpness of your images.

As to whether it hurts or helps when on a tripod, I don't know for sure. I have tried to prove it both ways and am no convinced.

But I am using a really substantial tripod. That can be the factor that makes the difference. Flimsy tripods are useless.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

diverhank — Mon, 11 Sep 2017 17:43:09 GMT

@Carlosbuddie wrote:
Hi Bob,
Tried all that, I have tried just about any and every combintaion of anything I could think of all to no avail. 😞

The only thing you haven't mentioned trying is check the option "Lens Drive When Focus Impossible" and make sure that it is set to continue to focus (can't remember if this is 0 or 1). For whatever reasons the camera thinks focus is impossible (it is often wrong), it stops focusing.

I do have a 600mm f/4L lens that I use with the 7D2 and 5D3 and they work perfectly with both the 1.4 and 2.0 installed and the option set to continue to try to focus. I discovered this option due to problem focusing with the option set to stop.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 20:06:15 GMT

Thanks for your reply, thought you were onto something there but no luck still the same 😞

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 20:12:00 GMT

Thanks for your reply.

Yes I had noticed that on mode 1 the IS seems to Hunt for a couple opf seconds before settling down. mode 2 seems to be a little quicker.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Carlosbuddie — Mon, 11 Sep 2017 20:32:10 GMT

Thanks for you epic reply TCampbell. 🙂

You seem to have grasped what I was getting at, IE if it all works on an old 60d then it should work (better) on the 7dmk23 and the 5dmk3.

Yes on a solid tripod.

Not windy.

Shutter speed 1/1000 to 1/1250 at f11 iso 400, no mirror lock up mode.

Subject not moving ( see image of Eagle in other post with same title)

Yes, remote release.

Yes fairly hot about 30 c but same temp for all three cameras.

I have tried micro adjusting the lens and converters, not with a chart but a stationary object and changing the - or + by a couple of segments at a time between images, but no difference.

If you look at the image of Eagle in other post with same title you can see that the whole image is well out of focus front and back. The AF point was dead on his back at about 200 feet or between 50 m and Infinity, closer to infinity.

Manual focus gives the same result, out of focus.

The lens is brand new as are the converters (Canon)

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

Waddizzle — Mon, 11 Sep 2017 23:02:25 GMT

I think I asked before about what focus mode and AF points are you using.

How do you have the options for continuous shooting? Focus Priority or Shutter Priority? I always set this all the way towards Focus Priority, because what is the point of taking a rapid sequence of shots if they are not in focus.

Re: Focus problem with 600 mm IS 2 plus 1.4 and 2.0 TC's

TCampbell — Mon, 11 Sep 2017 23:23:08 GMT

It's a bit difficult to tell much from your eagle shot because the image is small when posted online (do you have a full-res image posted somewhere?)

Anyway, you don't necessarily have to buy a commercial focus test target since the principle is fairlly simple.

Imagine having a flat high-contrast target.

Now imagine laying a yard-stick / meter-stick on a slope so that the low end is nearest to the camera and the high end is farthest from the camera and the mid-point of the measuring stick is adjacent to your flat focus target.

Use single-point AF, select the center point, and focus on the test target (solidly on the test target - make sure there's no chance the AF point missed the intended target).

Now download the image and carefully inspect... not the target... the measuring stick adjacent to the target. Since it was on a slope you should be able to see the enter stick from front to back. You're looking to see if the some point along the stick appears to have better focus than the intended focus point.

Here's an example that I did with my EF 300mm f/2.8L IS USM (original).

The focus target should be at about 25x the focal length (for lenses longer than 200mm). 300mm x 25 = 7500mm. That's 7.5 meters (24.6 feet).

I measured out a 25' distance (close enough)

I needed to find a high-contrast target so I used a Lego model of a rocket. I also grabbed a measuring scale (in my case a metal 60" scale).

I placed the scale adjacent to the rocket body so that my intended focus point (I pick a bold high-contrast point where the black & white meet) were at the 30" mark (and later discovered it was in fact nearer to 29.5" and not my intended 30")

Camera is on a tripod using the f/2.8 focal ratio (shallowest depth of field available for this lens)

I turned off image stabilization and deliberately de-focused the lens (to force it to focus) and took a few shots. Here's a sample:

It's a bit difficult to read the scale without cropping in, so here's a cropped in section.

Remember that the point on the scale which is even with the front of the rocket body (the point I chose was the top of that black stripe).

Now I inspect the scale. I can see that the 27" mark is going a bit soft. Likewise I can see the 32" mark is going a bit soft. The 28 and 31 marks look a bit better. The 29 and 30 marks both look equally good to my eyes. And I also confirmed by walking up and re-inspecting the scale & target that it was, in fact, the 29.5" point where the rule was at the front of the rocket body (not the 30" mark that I intended... the scale slipped a bit after I laid in position).

In this case my lens nailed the focus bang-on accurate.

Anyway... you get the idea. You don't necessarily need a commercial target if you set up a valid test.

Since you have a 600mm lens with a 2x teleconverter, that's 1200mm, the target should be about 30 meters from the camera body (quite a distance) - which is why I suggest using a larger scale rather than a commercial test target (which tends to be small).