New 100-400L on the way

shinksma wrote in post #16062830
Out of curiosity, had you sent it in to Canon to see if they could adjust it for improved performance?

At times my 100-400 blows me out of the water, and at times it is frustrating due to slower AF (which also causes sub-optimal AI-servo operation) (probably being f/5.6 at 400mm not helping), a tendency to focus on a background object rather than the item of interest (happens with birds in trees a fair bit, annoyingly), and yes, overall softer than my 70-200 IS II (well duh, the 70-200 IS II is the sharpest zoom lens Canon offers, AFAIK).

I'd be OK with a 300-400 f/4, if Canon could swing that for a fair price. I realize that the primary factors driving optics are the biggest aperture at the longest FL, so maybe that design isn't much less expensive/complicated than the 200-400 without TC. And I don't see Canon releasing even a refreshed 100-400 f/4.5-5 for less than $2500. I am happy to be surprised, though...

shinksma

It had been with an authorised Canon Dealership...so is that the same ?

Its the only lens I had that was bought used - and the only one I haven't been happy with

hania wrote in post #16067388
It had been with an authorised Canon Dealership...so is that the same ?

Its the only lens I had that was bought used - and the only one I haven't been happy with

No, that's usually not the same...the dealer is just trying to sell the lens (possibly a trade in on a new lens purchase), they don't usually have any wherewithal to have the lens "serviced". If you send it in to an official Canon repair/service centre (UK spelling!), they will be able restore it to like-new operation/condition.

I'm not sure of the cost for such a service in the UK, but you can call and ask what their minimum "look under the hood" (yuk yuk yuk) charge will be.

Oh wait, since you are in the UK, that should be "look under the bonnet", which has nowhere near the same pun factor...

shinksma

shinksma wrote in post #16069179
No, that's usually not the same...the dealer is just trying to sell the lens (possibly a trade in on a new lens purchase), they don't usually have any wherewithal to have the lens "serviced". If you send it in to an official Canon repair/service centre (UK spelling!), they will be able restore it to like-new operation/condition.

you definitely want to do that if it needs servicing

watt100 wrote in post #16073118
you definitely want to do that if it needs servicing

Sorry, may have confused you all - it was with an authorised Canon repair Centre (local ).

It had a repair in March (both the contacts on my 7D and on the 100-400 needed replacing - failed at end of workshop in Poland).

Zoom ring also replaced and all calibrated (so service docket said).

Took it to Irish Sea Bird workshop June - found it was rubbish under f8 and not much better above .(checked by tutor).

Fortunately I also had my 70-200 2.8 with me - so I managed.

Once home I took it back again as still under 6 month warranty : they said the focus module had failed so they replaced it.

Did set of 100% crops at all f-stops and sent them to tutor - who said that the lens may be within Canon's tolerances, but is still very soft!

Looking at the results I got from my 70-200 I see what he meant.

I have sold it now to local used camera dealers.

hania wrote in post #16075134
Sorry, may have confused you all - it was with an authorised Canon repair Centre (local ).

It had a repair in March (both the contacts on my 7D and on the 100-400 needed replacing - failed at end of workshop in Poland).

Zoom ring also replaced and all calibrated (so service docket said).

Took it to Irish Sea Bird workshop June - found it was rubbish under f8 and not much better above .(checked by tutor).

Fortunately I also had my 70-200 2.8 with me - so I managed.

Once home I took it back again as still under 6 month warranty : they said the focus module had failed so they replaced it.

Did set of 100% crops at all f-stops and sent them to tutor - who said that the lens may be within Canon';s tolerances, but is very soft!

I have sold it now

Ah, OK. Do you have those crops handy still? I would be curious to see how they compare to my lens' behavior. The 100-400 is certainly not known to be Canon's sharpest lens anyhow, though.

This is drifting a bit off-topic (after reviewing this, maybe I should start a new thread elsewhere, but I'm sure it has been written many times over...), but I was poking about the interwebz yesterday, and came across a variety of articles about lens theoretical resolution capabilities vs sensor resolving power. Now, this is no excuse for the 100-400 to look far worse than the 70-200, but does seem to indicate we are nearing some physical limitations in modern lenses and sensors.

A rule-of-thumb for resolving power is something like:

For a lens:

700/(f-stop) = lines pairs per mm

So any lens, at f/7.1 (f-stop 7.1), resolving power is just under 100 line pairs / mm (lp/mm).

And for a sensor, the line pairs / mm is just half the lineal pixel density (# pixels wide / physical width, divided by 2 for "line pairs").

For a T3i or 7D APS-C sensor, quoting numbers from a canonrumors forum post by jrista (a lot of other info is well presented in that thread at CR, but I did read similar stuff elsewhere, so it isn't my only source!):

Thus, any lens at or beyond f/8 is being outperformed by the sensor of any of the newer ~20MP APS-C cameras.

Wide open, say f/2.8, a theoretical lens should resolve to 250 lp/mm, which is well beyond pixel density of APS-C sensors. However, other limitations to lens design can start to be noticed, which I guess is why good lenses peak in resolving power at about f/4 or so.

Now, the rule of thumb I used, 700/(f-stop), may be making a lot of assumptions. For example, it assumes a contrast ratio MTF of 50% is needed to resolve extremely fine line pairs on a digital sensor, whereas human vision is reportedly about 9%. If human vision is used as a guide, you can use a rule of thumb of about 1500 / f-stop. Which means you need a sensor of about 90MP to start out-resolving a lens at f/7.1.

So maybe improving sensor performance for lower contrast is the next frontier in performance improvement.

I can't recall in my browsing if there is any opportunity to cheat the theoretical MTF limits. If not, then the only other opportunity to improve lens resolving power is improving lens performance at lower f-stops, but sometimes you need/want higher f-stops to get a useful depth of field.

Sigh, darned physics!

shinksma

Hi- have posted the 100% crops on the main forum under "soft 100-400"

shinksma wrote in post #16075177
I can't recall in my browsing if there is any opportunity to cheat the theoretical MTF limits. If not, then the only other opportunity to improve lens resolving power is improving lens performance at lower f-stops, but sometimes you need/want higher f-stops to get a useful depth of field.

There is a way to take multiple pictures of a non-moving subject and get a higher resolution then a single image will attain. It is similar to the HDR process and I think there is a way to do it in PS CS6 extended and I think a couple of cameras have this capability built in (like a hassy H5D-200).

Just never needed to do this, so not sure how and don't have the time to look it up, only I know it can be done.

watt100 wrote in post #16061388
really, the current 100-400 is incredible, why upgrade. I used it last weekend indoors at the zoo

f5.6 - 400mm - 1/400 iso 3200

Great picture!

If it has a zoom ring, instead of the push pull zoom I might get one.

HoosierHorridus wrote in post #16106376
If it has a zoom ring, instead of the push pull zoom I might get one.

For such a long zoom, I like the push/pull. I've used the 70-300L and it feels like I have to twist it too much to use the full range.

mike_d wrote in post #16106447
For such a long zoom, I like the push/pull. I've used the 70-300L and it feels like I have to twist it too much to use the full range.

Thus the nick name "Dust Pump" I guess if it was sealed better than the copy I had I might consider a push pull version.

HoosierHorridus wrote in post #16108722
Thus the nick name "Dust Pump" I guess if it was sealed better than the copy I had I might consider a push pull version.

You can't seal a zoom lens that moves in/out when zooming. It matters not one jot whether the lens moves in and out via a push/pull mechanism or a twist mechanism, air will still have to move in and out.

mike_d wrote in post #16106447
For such a long zoom, I like the push/pull. I've used the 70-300L and it feels like I have to twist it too much to use the full range.

Owning both the 100-400L and the Sigma 120-300 OS (most commonly used with the 1.4x or 2x TC) I find that the Sigma, with its twist zoom, is actually much easier to use than the Canon, despite its greater size and weight. The lack of zoom creep is also a very good thing - with the Canon, if the friction is set high enough to avoid zoom creep, it becomes too hard to zoom, while, if you set the friction to be able to zoom in and out easily, the lens creeps out to full extension almost immediately if you sling the camera over your shoulder, put it around your neck or put it in a waist holster.

For what it's worth, the new Nikon 80-400, as well as the Nikon and Canon 200-400s, also use twist zooms.

i find using my sigma 150-500OS as a push pull as the easiest fastest way to zoom...using the actual twist zooms seems like the worst idea ever...it's so much easier to just push, and pull...

Shadowblade wrote in post #16109466
with the Canon, if the friction is set high enough to avoid zoom creep, it becomes too hard to zoom, while, if you set the friction to be able to zoom in and out easily, the lens creeps out to full extension almost immediately if you sling the camera over your shoulder, put it around your neck or put it in a waist holster.

I've never found a sweet spot of tension. So I just unlock it when in use, and lock it when its hanging. I put a black "livestrong" type band around the locking ring to give more grip so I can unlock it with one hand.