Messages

7306

EOS Bodies / Re: Bokeh difference - full frame vs crop??

« on: October 27, 2011, 11:52:10 AM »

sorry, neuroanatomist, but your math is wrong: you have to multiply by 1.6, not by 1.3
135mm f/2 on APS-C is exactly equivalent to 216mm f/3.2 on full frame, not f/2.8

Yep, you're right.  I only added a stop, not 1.3 stops.

also, number of blades is relatively irrelevant for bokeh, unless you're worried about bokeh while significantly closing down the aperture on the lens, which is not the most common scenario

Agreed, although I do occasionally shoot portraits stopped down a fair bit to increase DoF when necessary.  Even then, it's not just number of blades, because some lenses have the edges of the aperture blades rounded, which makes a difference.  In the TDP reviews of the Canon 50mm primes, Bryan includes a bokeh comparison.  All are at f/2.8, but the rounded blades of the 50/1.2L (left) retain a circular shape for the OOF specular highlights, while the 8 aperture blades of the 50/1.4 (middle) and the 5 blades of the 50/1.8 (right) are evident.

I know because I have run A LOT of bokeh tests

I've run across your tests before - great work!

7307

EOS Bodies / Re: Bokeh difference - full frame vs crop??

« on: October 27, 2011, 11:08:05 AM »

lens construction i.e. number of blades making the aperture makes a difference, sensor size is irrelevant..

Not just number and shape of aperture blades, but also the degree to which the lens is optically corrected.  For example, Canon designed the 50mm f/1.2L with intentionally undercorrected spherical aberration to increase the quality of the bokeh (and that slightly decreases sharpness wide open for that lens).

Also, sensor size is relevant for the reason I mentioned above - the effect of optical vignetting on the shape of OOF highlights.  Vignetting causes cat's-eye shapes at the edge of the frame, and when you use an EF lens on an APS-C body you are cropping away that portion of the image circle.  Check out the photozone.de bokeh comparisons for the 50mm f/1.4 on FF vs. APS-C.

7308

Lenses / Re: Will it be a EF 14-24 2,8 L is from Canon

« on: October 27, 2011, 10:42:18 AM »

I think that the EF 16-35 needs a replacement because of the bad performence on f.2,8.

Bad performance?   

7309

EOS Bodies / Re: Bokeh difference - full frame vs crop??

« on: October 27, 2011, 10:32:46 AM »

Thanks - I did allude to a difference between bokeh and DOF. Vignetting can be corrected somewhat with post-processing.... closer to the centre of the image, what sort of real difference in QUALITY of bokeh are we talking about?

None. 

Another side note, though - vignetting correction in post processing 'fixes' the light loss, but certainly will not alter the shape of the OOF highlight spots.

7310

EOS Bodies / Re: New 5D mk ll...Issues?

« on: October 27, 2011, 07:27:20 AM »

1) The DOF is incredibly thin. Love it!

Yep.  1.3-stops thinner, to be exact (i.e. if you set the aperture to f/2.2 on your 5DII, you'd get the same DoF if you framed a similar shot on your 60D af f/1.4).

2) Quite a few of the images are soft. I am manually focusing the majority of the time, and even tried AF. It still seems soft. The IQ seems comparable to my 60D which is not what I was expecting. The lens has always worked flawlessly for me, but something just seems off.

Three things going on here.  One is that the lens does have some halation at f/1.4-f/2 (a glow-like effect).  Two is that your autofocus might be off.  For the AF shots, you may need to perform an AF microadjustment (ideally with a tool like the LensAlign MkII or SpyderLensCal) - AFMA allows you to fine-tune the AF performance of a lens to a body, and is a very nice feature that the 60D lacks.  That's especially important for wide aperture lenses where the thin DoF reveals any small errors in focus.

But, you manually focus most of the time, so AF isn't the issue?  If you are using Live View at 10x to manually focus, then it's likely just slight lens softness at wide apertures.  But if you're focusing using the viewfinder, your focusing screen is the problem.  Stock focusing screens in all current cameras are laser microetched to be brighter with slow lenses (so they work better with consumer f/3.5-5.6 zooms).  A consequence of that microetching is that the DoF yo see in the viewfinder is equivalent to about f/2.5, even with a wider lens.  Try an experiment - normally when looking through the VF, the lens aperture is wide open, but when you use the DoF preview button between f/2.8 and a narrower aperture, in addition to seeing the true DoF you also notice the VF getting darker.  But with your 50/1.4, try holding the DoF preview button and adjusting the aperture from f/1.4 to f/2.5 - notice, the VF isn't getting any darker.  Nor is the DoF changing, because the VF won't show it.  So, you are manually focusing at f/1.4, but judging focus based on the deeper DoF of f/2.5 - meaning you might miss when you get the real DoF in your image.

The solution is the Canon Eg-S focusing screen, which is a matte screen that will show the true DoF of your fast lenses.  Great for MF with fast primes, but with an f/5.6 lens indoors, the VF will be really dim.

3) When I shoot in full auto, the ISO only reaches to 3200. When shooting manually, I am able to kick it up to 6400 (yes the noise is horrific) but why might this be?

The 60D has user-selectable max ISO for Auto ISO, previous cameras do not.  So, Auto runs from 100-3200 and there's nothing you can do to change the max (or the min directly, althoguh using HTP will up that to 200).

7311

EOS Bodies / Re: How weather resistant is a 5DMK2 really?

« on: October 26, 2011, 11:16:40 PM »

Unfocused, I can't speak to most components, but a bit of time in a hot trunk is a great way to permanently damage your Li-ion batteries, especially if they're fully charged or close to it at the time.

7312

EOS Bodies / Re: Bokeh difference - full frame vs crop??

« on: October 26, 2011, 10:29:22 PM »

There will be a difference in the depth of field, if you frame the shots identically the FF sensor will give a shallower DoF, by a factor of 1.6 when comparing FF to APS-C.  So, the APS-C will give a depth of field equivalent to setting the aperture on the FF camera 1.3 stops narrower (because stops are a base-2 log scale, and the base-2 log of 1.6 = 1.3).  Put another way, 85mm f/1.2 on a crop body is approximately equivalent to 135mm f/2 on FF, 135mm f/2 on APS-C is approximately equivalent to 200mm f/2.8, etc.  Again, this applies if you frame the shots the same on the two bodies with the same lens. 

The reason is distance - because 85mm on APS-C yields a field of view equivalent to 135mm on FF, to get the same framing you must be further away with the APS-C camera.  That increased distance results in a deeper DoF.

You can prove it to yourself with the numbers, plug whatever you like into DoFMaster's DoF calculator.  They also have a page on the effect of crop on DoF. 

As a side note, this isn't bokeh.  Technically, bokeh is the quality of the OOF blur, and is a property of the lens and the elements in the picture.  A crop sensor affects the quantity of OOF blur. 

Well, ok, that's a simplification, since a crop sensor can affect bokeh with some lenses - in some cases, vignetting results in OOF blur spots at the edge of the frame that have a cat's eye shape, which is less pleasing than a round shape, and to the extent that using an EF lens on a crop body reduces vignetting, it will result in rounder OOF blur spots, which would be considered better bokeh.

Hope that helps...

7313

Lenses / Re: Lens Announcement [CR1]

« on: October 26, 2011, 08:45:38 PM »

I'm not expecting the entry level primes nor the slower selling L primes being updated ever.  The quality of zooms has improved to a level approaching many L lenses, times have moved on with digital tech to push the ISO performance to greater levels than ever...   In all seriousness, how much better is a 135mm f2 than a 70-200mm f2.8 IS II when considering the flexibility of the zoom.

What primes sell well? 

Does anyone really need f1.2 DOF ?

I agree on the entry level primes. But would you call the 85L a fast selling lens? It was updated on 2006. Since then, every other L prime at 100mm and under - except the 35L - has been updated or is a new release. I'm pretty sure we'll see a 35L II at some point.

The 70-200/2.8L IS II is an amazing and versatile lens, and it's my second most used lens on my 5DII.  But, my 135/2L is better - and also the only option - when I need f/2 for either the background blur or the extra stop of shutter speed.

I do frequently shoot at f/1.2 on my 85/1.2L II. 

7314

Lenses / Re: New lens... err body?

« on: October 26, 2011, 07:27:49 PM »

For birds, I'd definitely take the 7D over the 5Dc with the 70-300 L. 

What lens were you planning to get to use with the 2x TC?  Your 70-300 L cannot take a Canon TC.

I read a review that it takes the Mk. III converters. The guy shot some pics with the 2x Mk. III

Ahhh the Internet, fountain of Truth.   

7315

EOS Bodies / Re: No 5D Mark III on Novemeber 3 [CR2]

« on: October 26, 2011, 03:39:35 PM »

On another site, I read someone's hands on review of the 1DX and he said he overheard two Canon employees hinting at the November announcement. The writer said that it would make a lot of people happy.

It's a Hollywood announcement. Maybe it's an X Mark I Electronic Clapperboard that will make a lot of 2nd ACs happy...   

7316

EOS Bodies / Re: No 5D Mark III on Novemeber 3 [CR2]

« on: October 26, 2011, 01:52:13 PM »

You forgot to factor in what Nikon does as well.

The D700 already has a 51 point system which is IMO better than everything currently available on the market besides the 1DX

Not really.  As I've stated before, the real competition between the two companies plays out on the battlefield of P&S cameras and entry-level dSLRs.  By the time comsumers are considering a high-end or pro body, most are invested in a system and inertia means they won't switch (empty threats on internet forums notwithstanding).

Why is the D700's AF better?  It's got 51 points, but if that's the basis, then more MP automatically make a camera better, too.  Physics and geometry tell us that the wider the baseline for a triangulation measurement, the more accurate the measurment.  AFAIK, all Nikon AF systems use f/5.6-sensitive line sensors.  Canon systems have up to f/2.8-sensitive line sensors, which are more accurate than f/5.6-sensitive points.  Just one more thing to consider...

7317

EOS Bodies / Re: How weather resistant is a 5DMK2 really?

« on: October 26, 2011, 12:34:55 PM »

I don't know of any authoritative sources on this.  My statements are based on information in the Canon Camera Museum and statements made by Chuck Westfall.

I agree that there won't be formal testing on this (who can afford to test these things to failure?).  There are ISO standards for shock and water resistance of some product lines (e.g. watches), and there some products that publish specifications for their resistance (e.g. I have a GPS unit that can be dropped from 1 meter and submerged in up to 3 meters of water).  Shock resistance, in particular, becomes an issue for a camera with internal moving parts that must be carefully aligned with other parts.

Personally, I have taken my 7D + 24-105mm f/4L IS out in rain showers - I wouldn't call them downpours, but definitely more than mist or drizzle, enough that I needed a raincoat and my hair was soaking wet when I came in.

I suspect the other contributing factor is build tolerances.  So, two different lines may have similar types of sealing, but the line with tighter build tolerances will actually be more water resistant.  Reportedly, build tolerances are much tighter for 1-series cameras than for other bodies.

7318

EOS Bodies / Re: No 5D Mark III on Novemeber 3 [CR2]

« on: October 26, 2011, 12:24:01 PM »

So out of curiosity, I'm looking at the EOS 1v vs EOS 3 (the EOS 3 replaced the EOS 5)

Notable differences (aside from the build):

...and frame rate.

7319

EOS Bodies / Re: Stories from Pro Solutions 2011 - London

« on: October 26, 2011, 12:21:47 PM »

I note one line from the linked article on the 1D X: "Canon tells us that the EOS-1D MK IV will continue, so those who like the 1.3x crop factor can still opt to buy that camera."  All previous statements indicate the 1D X is replacing both the 1Ds III and the 1D IV.  Any other confirmation on continued production/availability of the 1D IV?

7320

EOS Bodies / Re: Does a Digital camera need SLR?

« on: October 26, 2011, 12:05:52 PM »

No matter how good or fast the contrast-detect algorithms can be run, it still has to guess at the direction of focus adjustment, move the focus element a little, measure again, rinse and repeat.  That physical process of the adjustment can't be overcome by faster processing.

Could it be helped by faster processing?  Take two measurements and extrapolate to the direction and magnitude of adjustment?  Maybe that's already being done.  I agree that even so, it will never be as fast as phase detect.  But maybe fast enough in some cases?  AF times and shutter lag on P&S cameras are growing shorter, albeit slowly.