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Messages - Plainsman

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Lenses / Re: True reach of 100-400 L II
« on: February 28, 2015, 03:06:37 PM »
Hi, I just compared my f/5.6 400 L to the new 100-400 L II.

Image quality difference that I perceived is more or less like displayed at "the digital picture". In short: In the center, the 100-400 L outperforms the 400 L by just a bit, in the corners, the 400 L is better and also, the distortion of the 100-400 L is more pronounced.

But that's nothing new. However, there is another striking difference: The reach at "400 mm". I have no means of testing the absolute focal length of both, but assuming that the focal length of the 400 L is exactly 400 mm, then the longest focal length of the 100-400 II is only 363 mm. If found that by measuring lengths in images of testcharts, taken with both lenses from the same spot. Distance to the test chart was 6 m.

I already knew, that the indications of focal lengths of zooms are often rounded up quite a bit. For instance, my 200 L II + 1.4 extender (= 280 mm) gives practically the same reach as the long end of my 70-300 L.

But in the case of the 100-400, I find the rounding a bit over the top. I didn't examine the wide end, but let's assume that the 100 mm are correct, the we are talking about a 100 - 363 mm lens.

And anyone wants to add reach with a 1.4 x extender must know that he doesn't get 560 mm (which could maybe still be described as "almost 600 mm") but in reality, he gets 509 mm, which of course is something very different.

Again, my calculations assume that the 400 L is 400 mm. If its real focal length were 440 mm, then the long end of the 100-400 would really be 400 mm, but I heavily doubt that.

Does anyone have measured the real focal lengths? Also, I know that the focal lengths sometimes change with distance. I could do the same test with targets at infinity ... but maybe someone of you has already done that?

When Canon states that a focal length is 400mm - whether that's a zoom or prime - it WILL BE 400mm at infinity.

In practice "infinity" may typically be as close as a couple of hundred metres but at 6m there will be a big focal length loss probably more so with zooms than primes i.e. some parabolic type relationship where image size changes more rapidly at close quarters

At app 200m I compared the image size of the 400/5.6 and the 100-400 and found they were almost
exactly the same i.e. @200m if the prime was actually 400mm the zoom was also the same.

Lenses / Re: Review: Canon EF 100-400mm f/4.5-5.6L IS II
« on: February 16, 2015, 07:11:21 AM »
Hellishly expensive lens if you want it to reach 560mm.

This lens plus TC plus 7D II will set you back close to £4000.

Now a Tamron 150-600 (or the equivalent new Sigma C - due March) plus the new hi-res 760D (coming soon) will give you much much bigger images to work with......for only about £1700!

EOS Bodies / Re: Bingo! New Canon 5Ds has 50.6 MP new rumored specs
« on: February 03, 2015, 03:43:36 AM »
This is could be just a very expensive "show-off" camera to show they can do it.

More realistically what are the chances of the rumoured 24.2Mp 750D? I think highly unlikely as it would crash the sales of the 70D. So overall (maybe) not so much progress.

For Nikon users this will be a very sharp light weight prime capable of stellar performance with a high res body like the D7100 - great for airshows, BIF etc....

EOS Bodies / Re: Canon EOS Rebel 750D Spec List [CR1]
« on: January 21, 2015, 11:32:09 AM »
24.2 Mp on the smaller Canon sensor must be equivalent to more than 26 Mp on a Nikon sensor.

It would be revolutionary for Canon to leap ahead of Nikon - so it is highly unlikely!!

Lenses / Re: Canon EF 400mm f/4 DO IS II USM Lens Review
« on: January 17, 2015, 03:40:55 PM »
...beautiful short fat lens that would look even better in black!

Lenses / Re: canon 7D2 with 100-400 ii lens with 1.4 Extender for birds
« on: January 15, 2015, 03:55:22 PM »
I love the combination of the 7DII, 1.4III and 100-400 MK II for walking around birding. I have said this several times in this forum and have posted shots taken with this combo in Bird Portraits and BIF threads.

With a 1.4TC you need to stop down min half a stop to recover some of the loss of definition inevitable with a TC - so that will be give you a 560/9.5 at best.

Now with all due respect that is hardly a good combo for walking around birding unless you bring a tripod with you.

PS A Tamron 150-600 @600/8 would be better and a lot cheaper - and avoids separating the camera from the lens to install the TC!

The MTFs are consistent with those reported by lenstip.It beats out the Tamron wide open at 150 and 300mm, but is very similar at the crucial 600mm - see also the review of the Tamron

at f/8, there is nothing between them at any f. Again, the reviewer complains about the weight.

Here are the MTFs from the ePhotozine site, which is doing brilliantly for rapid reviewing (sigma = upper, tamron lower).

Why don't they give numbers to the y=axis instead of vague subjective "excellent" etc. and at least say at what distance the "tests" were done.

Distance is important because the excellent nikon rumours test on this lens indicated it was becoming very sharp beyond the usual 40ft test range.

I hate subjective reviews!

The resolution MTF curves look exceptionally good - as good or better than the 100-400vII?

Allied to a high res body like the D7100 it should outclass say 7DMKII with 300/4.

But Canon are ahead with their TCs so this lens could be extended to 420 but maybe no further.

Lenses / Re: Lens 'resolving power' vs sensors.
« on: January 05, 2015, 07:15:18 AM »
JRISTA, I would just like to say, "THANK YOU" for posting this enlightening info, (and even doing so without a grandiose, self-absorbed ego, I might add). You obviously have a serious optical engineering fund of information. Aside from thanking you, I am posting here so I might be able to search this post again and read it a few more times.  Again, thanks!  :)

I would also like to add my appreciation to jrista for his posts which always include "numbers" in his explanations as well as worked examples.

To many bluffers on this site who have read a book or so and think they are experts on very technical matters.

Lenses / Re: Quick Comparison: Canon's new 400mm Options
« on: December 22, 2014, 11:40:03 AM »
I really want to see the in-field performance of the 400 f/4 DO II under different lighting conditions. If Canon has solved the DO weakness of poor contrast and flaring, and knows how to make super-sharp DO lenses, then we should expect to see a 500 or 600 f/4 DO someday - maybe 5.5 to 6 pounds, rather than the 7.0 and 8.5 pounds the version II conventional 500 and 600 f/4 weigh. Yeah, I know - unicorns.

I'm sure its possible, it depends on marketing.  Are there enough buyers in the market to go for a 500mm, a 600mm or a 800mm DO?  A lot of people recently invested a big chunk of money in the new 500mm and 600mm lenses, and are not likely to change to a DO version, so maybe the 800mm is the next DO lens??

I'm surprised you're so sceptical about DO with how much people raved about the weight difference between the Mk1 and Mk2 Big Whites.

My bet is all Mk3 Supertelephoto lenses will be DO, there really isn't much else they can improve otherwise.

I think by 2020 the 500 and 600 dinosaur primes could be replaced by a single 400 - 600/4 DO zoom unit.

Canon are getting the hang of DO now so this would be a natural developement - two for one! Primes are going to be replaced by zooms.

Lenses / Re: Quick Comparison: Canon's new 400mm Options
« on: December 19, 2014, 02:14:28 PM »
He must have picked an excellent copy of the original 100-400 for his comparison.  I'd say my version 1 lens is average but the version II lens is excellent.  My copy of the new one is much sharper wide open plus the much improved IS and twist zoom is a "must upgrade" if you use this lens a lot.

They tested four copies of each generation 100-400, and averaged the numbers.

....that's why LR results are more reliable than other reviews where probably only one unit is tested.

Lenses / Re: Quick Comparison: Canon's new 400mm Options
« on: December 19, 2014, 09:50:11 AM »
Wow! LR confirms that the 400DO centre is sharper than the new 100-400II by as much as the 100-400II is sharper than the 100-400I. Take that which way you want!

I've always known that my 100-400I was sharp and Roger Cicala's test proves just that. So doubtful whether I will sell it for the newer one now as I never crop at the corners!

BTW this is the first time I have seen quantitative MTF measurements for the old DO - thanks Roger.

Lenses / Re: 400mm DO II
« on: December 19, 2014, 07:20:40 AM »
Huge improvement over Mk 1.  The fact that Roger is using new test charts makes it impossible to really compare it to other lenses, but, still, it is significantly better than the 100-400 II and 400 DO I.

I would expect that with Canon's perseverance with DO that this will be a hugely improved ens - I mean a really sharp relatively lightweight 400.

Lenses / Re: Canon 100-400 ii Image Quality Review Posted at TDP
« on: December 18, 2014, 12:57:59 PM »
Looking at the crops compared to the tamron. They both look about the same at 400 f/5.6 the canon looks better in the corners at 560 than the tamron does at 600. If I didn't already have the tamron then I would get the canon.

Maybe you should wait for the Sigma 150-600 C version. With more LD lens elements it should outperform the Tamron but would be roughly the same weight and price.

It should be very good in the 400-600 range. We shall see - this time next year!!

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