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Messages - PeterJ

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Australia / Re: ND filters
« on: November 07, 2011, 01:38:58 AM »
I guess that is a reason for another trip to Tassie after I get hold of some black glass....
If you'll be down south try giving Walch Optics in Hobart a call, I haven't been in there myself yet (been meaning to) but a few people have told me they carry good stock of some more obscure and/or professional items. They might also be able to order one and have it ready for you to pick up.

Lenses / Re: How much!?
« on: November 04, 2011, 07:52:30 AM »
$45,000 for a lens. A new benchmark.
I believe the special order 1200/5.6L USM will set you back well over double that so maybe not a new benchmark, but still a bit outside my price range :'(

EOS Bodies / Re: Mobius by Vincent Laforet on the EOS C300
« on: November 04, 2011, 07:17:15 AM »
I just took a low-resolution screen capture of one of the frames (to avoid copyright problems) and noticed a 'baddy' appears to be shooting with all his fingers on the outside of the trigger guard.
No.  Look again.
Can't see it to be honest, still looks to me as though on that plane the trigger would be behind his index finger as normally used for the 'trigger' finger and you can see his knuckle clearly. I've recently started suffering from arthritis and now use my middle finger for any triggering including a camera and it's a mixed blessing because now I find while it might look odd I get a bit of extra stability from my index finger. In that shot though it looks like his middle finger would be below the trigger.

Anyway was just a bit of a fun post, I was thinking to myself that with increased video resolution a few production staff will probably need to get used to a bit more detail showing up. Not into video myself but I went on a tour of a movie set years ago and was amazed how unrealistic the set looked in real life when you'd never notice it at 480p or whatever the resolution of the day was.

EOS Bodies / Re: Mobius by Vincent Laforet on the EOS C300
« on: November 04, 2011, 04:37:17 AM »
I just took a low-resolution screen capture of one of the frames (to avoid copyright problems) and noticed a 'baddy' appears to be shooting with all his fingers on the outside of the trigger guard. Maybe this model includes some new wireless trigger options?

Lenses / Re: 24-70 f2.8L Zoom Ring Issue
« on: November 03, 2011, 09:47:46 PM »
I'd never really noticed during operation but just pulled mine out and it's the same - a little harder to turn at the wide end but smooth the whole way through. It seems to be at the stage the objective is extending more rapidly so guess it just has a bit more mechnical work to do.

EOS Bodies / Re: 1dx and Ethernet
« on: November 02, 2011, 08:51:21 AM »
I'd guess at a minimum it will have the FTP capability of the WFT units that include ethernet, so you could use an SSD in a netbook or laptop. Either that or load up a NAS appliance with some SSD drives, most need mains power but not a lot of current so you could use a small inverter.

United States / Re: Telephoto Zoom or Prime?
« on: November 02, 2011, 05:42:03 AM »
Agree with the all the above, one thing though is before you purchase do you have a chance to take a few test shots at the venue with a f/5.6 kit zoom or similar? Just thinking you could crank the ISO right up to give you a feel for what focal lengths you'll really need, I suspect 200mm on a crop will be too long for most shots. Just looking at a calculator to reasonably frame a horse and rider (assuming 4.5 x 3m FOV) you'd need to be about 40m away.

The 70-200 would be more versatile, but without IS depending on how steady you are and whether you're using a monopod or tripod you might end up needing to use a longer shutter speed than you'd normally want.

EOS Bodies / Re: 1DX and focusing screens
« on: October 31, 2011, 05:49:54 AM »
That means MF has the potential to be more accurate with a lens faster than f/2.8, if you can install a focusing screen that shows the true DoF of a lens faster than f/2.5 (the approximate cutoff of the standard focus screen).
I'd seen your explanation of that some time ago neuro and meant to say thanks. When I first got my 7D and was playing with the new features (compared to my previous camera) I tried the DOF preview on a 50mm lens. I only tried some of the wider apertures where I would have found it more useful and when I couldn't see a difference through the viewfinder put it down as a useless feature and never touched it again ::).

Out of interest what's the design decision that makes them go that way, is it because otherwise the view would be too dim with say an f/5.6 lens? Conversely are there reasons once you've installed a new focusing screen where you'd want to remove it for some lenses?

EOS Bodies / Re: The EOS-1D X & f/8
« on: October 27, 2011, 02:29:55 AM »
A crazy thought, but would it be possible that Canon are developing and planning to release a new 2x converter that reduces an f4 lens to f5.6 rather than f4- f8 especially for the 1DX, is this technically possible? :-\
It's not technically possible, it's a basic optical rule that a 2x converter results in 2 stops of light loss.

Edit - just to explain further the 2x extender means that now your lens is effectively only using half the the front area both horizonally and vertically, so it's gathering a quarter of the light or two stops. That's why you also halve the resolution of the lens which has a varying effect depending on the resolution of the sensor.

EOS Bodies / Re: How weather resistant is a 5DMK2 really?
« on: October 26, 2011, 11:53:58 PM »
Most commercial temperature grade components have a 0-60C operating range, but most have a storage temperature of 100C+ so I wouldn't be too worried about the electronics when left turned off. A reflow oven that they use to solder boards is normally held above 200C for a few minutes. As neuro said Lio-Ion batteries don't stand up to heat well and it degrades the life even if it doesn't destroy them.

EOS Bodies / Re: Does a Digital camera need SLR?
« on: October 26, 2011, 08:08:11 AM »
You don't really "need" one but probably the biggest advantage it brings to the table is the ability to use a seperate phase-detect autofocus system. The contrast detection systems that use the normal sensor are slow in comparison, although there are some new hybrid sensors I believe combine phase detection into the main sensor which I assume may work well.

You also get to see exactly what's coming through the lens without the lag or resolution loss of an EVF. I guess the only disadvantage to the viewfinder is in low-light if you can't see the subject, but personally in those situations I'm always using such a long shutter speed I use a tripod and live view anyway.

Out of interest do you own a DSLR or just learning a bit about the differences? If you've only used point & shoots before the speed of a dedicated autofocus system will blow you away especially when combined with a large aperture lens that lets plenty of light in.

Canon General / Re: Birders don't use Canons?
« on: October 21, 2011, 04:36:54 AM »
Not a movie but recently on TV news I saw a photographer with a 70-200 after a sporting event trying to take a few snaps of competitors holding the camera in the the air what must have been 50cm from the subject. Hope they had a few extension tubes in place ::).

Many additional elements factor in, resulting in final image quality: A/D converter performance (12bit to 14bit seems to produce a very high boost in dynamic range, noise performance etc.), image processor, firmware etc.
Excellent summary, on the above point for some reason I got smited last time I mentioned it up but a lot of people don't realise a high-speed ADC at 14 bit resolution is pretty cutting-edge when they want the extra DR we all desire. I just checked Analog Devices and their fastest 16-bit converter costs over $US100 for 250MSPS which you'd need for 32MP x 8fps but according to their datasheet only has a little over 12 bits of effective resolution.

What you can do is us more accurate but slower ADCs in parallel which is what Canon  have done with the new X model by using 16 in parallel I believe to get a fast reading time. For comparison I'm doing a job at the moment with a delta-sigma ADC that has 22 bits effective resolution, it costs < $5 but runs at around 10 samples per second, so capturing 32MP at that rate would take over a month.

Canon General / Re: Canon EOS 1D X Possible Press Release
« on: October 17, 2011, 10:35:12 PM »
It appears it could be true, if you take a look at the following press release on the Canon site it makes mention of the EOS-1D X with the same release date:


EOS Bodies / Re: New DSLR on Tuesday, October 18, 2011. [CR3]
« on: October 15, 2011, 03:12:38 AM »
But the Frames Per Second issue is not the motor in the cameras , it's the speed in which the sensor can dispurse its electrical charge , and prepare for the next shot - the sensor must drain , and refill with each image shot , and the speed of cicuitry is slowed the larger the sensor is , and the more power the CPU uses - so although they are comming up with new faster ways to charge and discharge the sensor , the MP always going up slowly balances it out from giving huge FPS increases. All we can hope for is a new rapid current charge and discharge that does not affect battery , or more seriously , sensor life span.
This probably needs a "citation needed" tag :P. Unless I'm mistaken I thought CMOS sensors were effectively a photodiode with an active amplifier, so the "refill" is caused the photoelectric effect and the discharge would consist of removing the small charge held by the inherent capacitance of the photodiode through a transistor. You need a certain number of photons of light to hit the sensor but if you're taking a 1/100s shot there's no reason each inidividual cell can't approach that in terms of fps.

General point is valid though, but it's not so much how quickly you can discharge the sensor it's how long it takes to do something useful with the output of each cell, namely taking an analog to digital conversion. That's largely a function of cost / size / power and then it has to be processed by a CPU and stored to memory fast enough which again is a function of cost / size / power.

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