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Messages - Edwin Herdman

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16
I use LV for any TS-E lens or macro-style shots.

Even for some wildlife photography it is useful if you have a moment to settle down and check focus, even with a big zoom lens.

Really it comes down to knowing what the situation calls for.  The viewfinder's main reason for being is speed and ergonomic use, at the cost of precision (at least since the Live View revolution; but before this, arguably I think you could say that viewfinders were a departure from the ground glass method of image composition).  I would have no complaints if I could use the viewfinder for everything, but I end up using Live View a significant portion of the time, at least half, outside of wildlife photography.

17
EOS Bodies - For Stills / Re: Too much dynamic range?
« on: November 20, 2012, 07:18:17 PM »
So my point is: with lower DR camera we'll have lower tone delta (difference of the initial color tone in the scene with reproduced tone by the sensor) when processing the low DR shot made using lower DR sensor.
I understand the question.

It's similar to the Adobe RGB versus sRGB space question - at least to hear Ken Rockwell tell it, aRGB sacrifices tonal gradations for gamut.  sRGB should allow for finer gradations in color change.

I think that before sensors will reach the limit of the current color space in terms of usable bit depth, the recorded bit depth will be increased.  If I am up to date with my reading, the analog-digital converter (ADC) is often claimed to be the stumbling block in this, but it is probably really the sensors themselves.  The ADC has to provide more precision than the original sensor capture data in order to preserve quality, so the actual bit depth ends up being a bit arbitrary (a best tradeoff).

18
Pricewatch Deals / Re: Black Friday at LensRentals.com
« on: November 20, 2012, 07:06:20 PM »
I keep blinking my eyes at these recent 5D Mark III prices.

But I have to admit I'm more interested to learn if there's a story behind the turkey PSA.  Exploding dinosaurs!

19
Yeah, if there was any one focal length that Zeiss might not have even bothered with for Canon, 135 might've been a good bet.  I'm sure the Zeiss will be very nice, but...
In addition to that, I was concerned about the minimum focus distance, given their statement that the new lens is for taking "detailed images from long distances," but looking at the stats its closest focus distance is .8M, or 100mm closer than the 135mm (900mm MFD).  That's pretty good.  Only hands-on use will reveal how the lens performs at different focal lengths, but even if it isn't a true APO design I'm expecting it to at least equal the EF 135mm.

Shame about the AF, as everybody else has noted, yeah - that is the one thing that prevents this lens from meriting a serious look to replace the EF lens.

20
Lenses / Re: A New EF 400 f/5.6L Before Photokina? [CR1]
« on: September 08, 2012, 03:20:25 AM »
Re the Sigma good or bad debate:

I (still) have a 120-400mm from them, it's not very sharp at 400mm.

I also have a 120-300mm OS from them, and it's sharp enough, and still fares well with a 2X TC on.  My only real complaint with it is the background OOF highlight circle can get very busy and this has ruined a few shots that should have been excellent - a crane fishing in a pond.

The IS also seems clumsy to activate, because often the first picture in a series is shake-blurred.  Remembering to let the OS (IS) spin up before you start taking photos helps of course.
5.6 is too slow for a prime....... like the 800-5.6?
f/5.6 is fine for 800mm because you already have a narrow enough angle of view for birds.  400mm users would like to pop on a teleconverter while retaining AF.

Trying to track birds at 600mm and up is quite punishing but I find that 400mm is (even on a crop like the 7D) at or even below the bare minimum to get detail on anything but a raptor or a flock of birds.  For single birds, especially small ones, I need that 600mm and a much closer minimum focus distance than 3.5M which is quite terrible actually.
The 400 F5.6 sells for $1350 in Canada. To get a longer Canon lens you have to be ready to shell out $9690. That's a HUGE jump in price.... and I'd be willing to bet that there is a market for something in between, like a 600 F5.6.

A 600mm f/5.6L would cost at least US$7,500. But a 500mm f/5.6L might come in under US$4,000.
It won't get made because they want to sell and make only 500mm f/4L lenses.

21
Pricewatch Deals / Re: Win a 5D Mark III Kit from Norman Camera
« on: September 08, 2012, 03:12:04 AM »
But seriously, what point is there in announcing a country-only contest on an international site?
What reason is there for Norman Camera to support this site?  I can just about walk over to their Kalamazoo location, after all (there used to be one here too)!  Silly CanonRumors, needing money to keep running and all. ;)

22
PowerShot Cameras / Re: Canon PowerShot Pro1X [CR1]
« on: August 18, 2012, 11:38:53 AM »
A little late to this party, but...

The original PowerShot Pro used (according to Steve's Digicams) a "2/3-inch CCD sensor" yet this rumor claims a full-size APS-C sensor.  If so, this would seem to either require a very large lens to ape the PS Pro's 28-200mm (f/2.4-5.7) zoom lens, or it will end up with a focal length range very close to the G1 X or (to an extent) the EOS M, so like others I don't see where this one would be positioned, other than perhaps being a sped-up G1 X (overcoming that camera's very slow continuous shooting speed).
Quote
AND they are drip proof
Even the TS-EL lenses?
There is no such thing as a "TS-EL," but yes, even "L" TS-E lenses are drip proof.  The TS-E 90mm (for example) is not an "L" lens, but the 17mm is.

23
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 10, 2012, 06:42:28 PM »
We're not talking about vignetting at the edges of an image.  We're talking about photosite wells blocking photons arriving at oblique angles, "per photosite vignetting" or shadowing, if you like.

Up until I wrote that post I thought that the cutoff was at f/2, but apparently it's actually f/2.8.  That's rather disappointing.  It probably changes from camera to camera slightly, depending on the sensor and photosite design (at the very least, it could change or someday be "fixed" in a new design).

24
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 10, 2012, 02:28:40 AM »
With current Canon cameras (up to the 7D at least), reports put the fastest aperture that increases light to the sensor at f/2.  If you shoot at f/1.4, the ISO is "invisibly" bumped (it still reports as say ISO 100 but the files are noisier than they should be).


I'm sorry but this is simply not true in any way shape or form.

Just so nobody is harmed by this breathtakingly assured response:

I must affirm that what I write is true.  I can mention some useful resources for understanding related phenomena: Expose-to-the-right and the non-linear response curves of digital camera sensors; the most relevant information for persuading you is in this thread and especially here.  In short, you, sir, are completely wrong.

If you would like to test it out, it is simple to see it in action:

Find a recent Canon camera, set ISO manually, and switch to A/v mode.  Slap a lens faster than f/2.8 on it (I thought it was f/2; it might actually be wider, I'll have to look at this again).  Shoot at f/2.8 and then shoot at the widest setting.  You will notice that the image is noisier (and, depending on the lens used, there may be vignetting as well, but this is not the important effect to notice).  By the theory, image brightness and noise should remain constant, since we are holding ISO constant, and exposure is simply light intensity * duration.  But quite obviously that is not what happens; the image becomes noisier.

In truth, the manufacturer's declared ISO settings are not scientific measurements - the scientific measurements given by DxOMark show that for every camera (regardless of manufacturer) the ISO sensitivities are not linear or even very predictable compared to what they "should" be.

I do not consider mentioning this issue to be a burden to other users, since it's fairly easy to comprehend (I gather that it is due to the narrow angle of current photosites restricting the angles at which light is effectively gathered, but in any case the effect is clear).

Digital SLRs are not film cameras, and the final image brightness and grain is affected by much more than just the user's selected settings.

____________

To the gentle users of the forum in general, I will leave with this final thought - DSLR "best practice" can be confusing to master.  The main thing to consider, if you want to have clean files, is to get as much information into the highlight section of your RAW by keeping the image bright without burning out highlights.  The second thing, of course, is to use low ISOs when possible.  Finally, there is a limit to how high you should crank ISOs in most Canon DSLRs; it is not necessary to get the image looking bright enough on the camera's preview screen, because that is not the final version of the image.  Instead, you may brighten the image afterward to retain your settings and a reasonable ISO.

How do you find the point at which brightening in post is better than pumping the ISO (obviously, if you just shoot JPEGs or can't be bothered, don't worry, but your image quality won't be as good as possible)?  Look at the sensorgen charts from the DxOMark data, specifically the point at which the "read noise" curve goes flat, no improvement (or even shoots upward).  On the 7D, that point is ISO 800 or 1600.  On the T1i, it was ISO 800.

How do you brighten the image?  Not with DPP.  Daniel Browning recommended RawTherapee last year; there is also The GIMP, Lightroom, or Darktable (a Lightroom replacement for Linux boxen).

It is worth mentioning that there are other losses at High ISO:  Dynamic range and saturation capacity (I believe saturation capacity is essentially a measure of how even the image is, since it measures the number of pixels that reliably reflect a gray target, instead of appearing in the final image to be some other shade).

The culprit, as Daniel Browning mentions, and also Gregg Siam, is that the photosites of Canon DSLRs don't respond equally well to light coming in from unusual angles.  In fact, slight purple and green fringing in some lenses has been blamed on this, as well.

25
EOS Bodies / Re: Should I get 7D now or wait for MKII?
« on: July 09, 2012, 01:13:34 PM »
The weather sealing will keep the camera controls dry, and that's probably most important.  For the camera mount, the prism box overhang should shield that a bit as well.  If you need more, you can always put together a bag over the lens.  Wear a wide-brimmed hat if you're still unsure.  Unless you really require absolute reliability and seek to either shoot in rain or keep shooting when it rains, I wouldn't call it a big deal.

26
EOS Bodies / Re: Should I get 7D now or wait for MKII?
« on: July 09, 2012, 11:53:51 AM »
I do plan on upgrading later on on a 5D body but not for the next 2 yrs. or so.
Start in the right place then.

For what it's worth, I do a bit of landscapes, and don't feel the need for ultra-wide lenses (my widest is a 17mm lens which comes out to somewhere around the same field of view as a 24mm lens on full frame).  There's nothing wrong with buying full frame lenses for a crop, as long as they are relatively newer or well-respected models.  The APS-C crop factor is a help with reach.  I'm three years into shooting and all of my lenses are full-frame compatible, but I won't switch mainly because the wider FOV would throw me for a loop (considerably less pixel density too).

The 7D is fine for landscapes, since you'll want to shoot at ISO 200 at most in most landscapes.

By the time two years have passed, we ought to be closer to a 7D replacement or a cheap full frame camera (possibly both will have been released by that time) and low-light performance closer to the new full frame cameras (cleaner images at higher ISOs will be very welcome).

27
Lenses / Re: A New EF 50 f/1.8 IS? [CR1]
« on: July 09, 2012, 11:45:34 AM »
With current Canon cameras (up to the 7D at least), reports put the fastest aperture that increases light to the sensor at f/2.  If you shoot at f/1.4, the ISO is "invisibly" bumped (it still reports as say ISO 100 but the files are noisier than they should be).  For a f/1.4 lens, this will effectively limit you to say ISO 200 if you wish to stick with "whole" (un-pushed, un-pulled) ISOs.  For the f/1.8 lens, that's a third of a stop and might prove more challenging to get a "whole" ISO out of.  Stopping down to f/2 is possible but I couldn't guess how good the OOF highlights will still be.

I'd much rather see another f/1.4 lens to replace the 50mm.  This cost cutting nonsense is not helpful.  Still, IS and STM or USM would be nice improvements.

28
EOS Bodies / Re: should i wait for 70D? when will it be here by?
« on: June 16, 2012, 03:08:59 PM »
From a marketing perspective, that wouldn't be a sound strategy because when dropping two digit xxd bodies, they'll forfeit the 40d legacy and there would be no stepping stone between xxxd and xxd. But other than that I still think you're correct, but the new cameras fusing 60d/7d will be called 70d, while a 5d2 successor will be called 6d.
Single digit > double digits.  The 7D hasn't broken with this tradition.

6D...lol

29
If you're interested in a fisheye and wanted it for an APS-C camera, this might be the better choice - it looks like it ought to make a full image on APS-C, whereas at some zoom settings the 8-15 won't cover an APS-C frame.

30
Canon General / Re: Crop factor for macros
« on: June 08, 2012, 10:28:27 PM »
But between the aperture lost from the extension tube, and the aperture lost from closing down the lens, you're sacrificing a good bit of light which would have been helpful to take the picture.  Macro is one of those times you can never have enough light.  Plus, it's nice to shoot wide-open or nearly so when going macro - depending on the lens some have nicer OOF highlights wide open.

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