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400mm F4 DO Lens MkII
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Re: 400mm F4 DO Lens MkII
Originally posted by brianvickers View PostSurely the 400 lens becomes a 560 with a 1.4 TC.....if its on a crop sensor body then the image frame would be equivalent to 896mm lens on FF....?
Me thinks there is a lot of confusion about all thisLast edited by eosbabie; 07-04-2017, 22:24.
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Re: 400mm F4 DO Lens MkII
As I said earlier Brian ,you simply don't use the sensor crop in the equation , otherwise we would all be running round with micro four thirds cameras with 500 mm lenses claiming that we are shooting at 1500mm with a tc.
It then just turns into a willy waving competition
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Re: 400mm F4 DO Lens MkII
Originally posted by the black fox View PostAs I said earlier Brian ,you simply don't use the sensor crop in the equation , otherwise we would all be running round with micro four thirds cameras with 500 mm lenses claiming that we are shooting at 1500mm with a tc.
It then just turns into a willy waving competitionEOS 7D mk II, Sigma 150-660C, Canon 17-85 EF-S, Tamron 10-24 and a wife who shares my obsession.
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Re: 400mm F4 DO Lens MkII
Originally posted by eosbabie View PostSo is my assumption right then.
The results will need no further explanation .
Anyway we seem to be getting nowhere with this so I look forward to seeing your published results from the new lens +tc combo
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Re: 400mm F4 DO Lens MkII
Originally posted by eosbabie View PostMounted on a 7D MkII and Combined with a Canon 1.4 Mk III Converter the DO becomes a 896mm at 5.6 with Autfocus, Fantastico.
Yes, in my 7D2 Manual the 400 f4 DO + x1.4tc is in group B so all AF points are available. With the x2tc it's in group G so AF is limited to the centre point + four assist points only. Still usable but less convenient.EOS 7D mk II, Sigma 150-660C, Canon 17-85 EF-S, Tamron 10-24 and a wife who shares my obsession.
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Re: 400mm F4 DO Lens MkII
Okay, I'll have a go at a few points that have come up, in the hope it helps more than piles stuff on top of other stuff:
(1) Using a smaller (aka crop) sensor changes the Field of View (FoV), i.e. you get a FoV equivalent to using a lens of (focal length) * (crop factor) on a 35mm (aka FF) camera. This is generally called "equivalence" and has limited uses (and is widely abused in forums). If people want I can list my caveats.
(2) A crop sensor doesn't automatically give you the resolution over a subject (i.e. "reach") that you'd get from using the equivalent lens on a FF camera, that depends on pixel density, lens quality, and a bunch of other stuff. Hence a 300mm lens on a 5Dsr actually should provide more resolution on a subject than the same lens on a 7DmkII despite the equivalent focal length on the 7DmkII being 480mm (due to having the same size pixels the lack of an AA filter). This is almost always abused by manufacturers as well as punters.
(3) You also have an equivalent aperture for noise and Depth of Field (DoF). Basically multiply the f-ratio (or denominator if you use 1/4 for f4) by the crop factor.
* Noise changes as the f-ratio is light per unit area, a smaller sensor captures less light. Almost all the noise in the image comes in with the light (away from the deep shadows where you can see the camera's noise, which actually decreases with rising ISO). The more light you capture the smaller percentage of it is noise (average noise is the square root of the light level).
* DoF changes, i.e. you get more of it with a crop sensor, simply as you are using a wider lens for the same FoV and the wider lens gives more DoF.
* Exposure doesn't change as that is based on light per unit area, which comes from the f-ratio (or T-stop if people are being picky).
Hence a lens used at f2.8 on a Canon crop sensor has about the same noise level (and DoF) as a f4.5 shot on a FF camera using the same shutter speed (but different ISO). (Note ISO is a post-light-capture effect, it doesn't make the sensor more sensitive, just amplifies the signal on the way to the digitiser to standardise the brightness, but does give the lower camera noise levels at higher ISO - too much info?)
(4) Extenders/teleconverters carry on the effect by their ratio. However I'd take issue with the suggestion you get the same AF functionality when using them, as Canon cameras have tons of ways the AF works and you have to look it up, but generally AF gets quite a bit worse as you add extenders and the equivalent f-stop changes. As an example on my 5Dsr my 300mm f2.8 L IS is in AF Group A, which gives five dual-cross points (basically it's the "all the goodies" mode). If I add a 1.4x it moves to Group C, which has no dual-cross points. With a 2x it's in AF group E, which also loses all the "superior tracking" AF points away from the centre block that A and C have. (See "lenses and usable AF points" in your camera's Instruction Manual.) BTW while some Canon cameras will AF only to f5.6 and others to f8 you can AF at lower f-stops (e.g. f11) using Live-View.Last edited by DrJon; 08-04-2017, 09:57.
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Re: 400mm F4 DO Lens MkII
Originally posted by DrJon View PostBTW while some Canon cameras will AF only to f5.6 and others to f8 you can AF at lower f-stops (e.g. f11) using Live-View.Hanging on in quiet desperation is the English way
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Re: 400mm F4 DO Lens MkII
Originally posted by eosbabie View PostI have that very lens, and I find it very good though short in reach.
While the DO is heavier Lens than the 70-300L, the Mass is more spread making it manageable to hand hold.
On the other hand the 70-300L Mass is in a short space and tends to make it feel slightly unbalanced.
Mounted on a 7D MkII and Combined with a Canon 1.4 Mk III Converter the DO becomes a 896mm at 5.6 with Autfocus, Fantastico.
With these two lenses my Wildlife photography will be taken care of for a very long time.
That's the Long and the Short of it for me.
Regards.Canon 6D; Canon 760D;Canon G15;Canon 40mm f2.8(Pancake);Canon 50mm f1.8(ii); Canon 17mm-40mm f4L;Canon EF-S 10-18mm f4.5-5.6 IS STM;Canon EF-S 55-250mm f4-5.6 STM lens;Canon 24mm-105mmf4L IS;Canon 70-300mm f4-f5.6 L IS USM;Kenko 1.4x HD TC;Canon 430EX ii flash;Giottos tripod;Manfretto monopod;Cokin P filters + bits and pieces!
www.flickr.com/photos/nathaniel3390
North Wales where music and the sea give a great concert!
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Re: 400mm F4 DO Lens MkII
So I have just tried using the 100-400 mki with a 2x mkii tc with my 1Div hand held in live view mode and it does auto focus, rather slowly looking out through our living room window. Field testing in proper light will show how well it does or does not work in real time, I don't think I'll be chasing birds in flight, but I think it may well have it's uses when stalking deer later in the year.Hanging on in quiet desperation is the English way
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Re: 400mm F4 DO Lens MkII
No Real shooting time with lens because of Weather, Quick shot from the other day.
No real editing just a crop shot for bare lens with no converter.
Can't wait for proper subjects, quality will be great I think.
0F2A7151.jpgLast edited by eosbabie; 23-04-2017, 15:39.
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