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Messages - neuroanatomist

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7966
Lenses / Re: 100mm 2.8L vs 135mm 2.0L
« on: December 11, 2012, 09:09:51 AM »
I merely wanted to confirm that a 100mm macro lens is just another 100mm lens, with a really small MFD.

Yes.

But comparing the 100mm macro with the 135mm at the same framing, DoF should be less with the 100mm macro.

No.

+1 but at the same aperture.

Body: FF
Aperture: F2.8
Focal length: 135
Focus distance: 10 meters (to get 2X magnification)
Total Depth of field: 0.97m

Body: FF
Aperture: F2.8
Focal length: 100
Focus distance: 6.75 (to get 2X magnification)
Total Depth of field: 0.81m

No2  :P

Your math is wrong.  135mm at 10 m will have a wider FoV than 100mm at 6.75 m.  For the same framing as 135mm at 10 m, the 100mm lens would be at a distance of 7.4 m [i.e. 10 m / (135mm/100mm)].  When you plug those numbers into your DoF Calculator of choice, you will find that for the same aperture the DoF is identical.

Here's the way it works: when comparing on a given sensor size (so we can ignore the circle of confusion), three factors determine DoF.

  • Aperture: wider = shallower
  • Focal length: longer = shallower
  • Subject distance: closer = shallower

When you are talking about the same framing, focal length and subject distance have equal and opposite effects, and thus they cancel each other out.  When comparing lenses of different focal lengths for the same framing, DoF is determined only by aperture.  So at f/2.8 for the same framing, there's no DoF difference between the 100mm Macro and the 135L, but the 135L can open up to f/2 meaning it can achieve a shallower DoF for the same framing.

7967
Big step backwards in AF? For who? I came from a 7D, why don't I feel crippled with my wife's 6D or my 9 point AF bodies shooting moving subjects? Oh. because the difference in AF is actually marginal with the need for better ISO performance outweighing the need for that said marginal AF performance.

If you're successful tracking anything with the 9pt af (esp. with shallow dof), you're a genius - whenever I tried I have to admit that there are simply too few focus points to keep the af, and of course the 60d has zero servo af customization.

But the 6d is bound to be better because of the better firmware options and esp. just the two af points more in the "gap" left+right from the center of the 60d-type af might make a difference - I'm still waiting for good reviews to decide.

The 5DII has 6 points filling that gap, as it relates to AI Servo.  Like Chosenbydestiny, compared to the 7D I found the 5DII and the T1i I had before the 7D, had no trouble tracking moving subjects.  Tree sloths, snails, flowing molasses, tectonic plates...the 5DII did just great!  My 3 year old running toward me across the back yard, with an f/2.8 lens, however.....

7968
EOS Bodies - For Stills / Re: Only 1 lens
« on: December 10, 2012, 10:16:59 PM »
Used 5DII prices have dropped so low you may not even be able to get a new 7D with the proceeds - there's a 5DII w/ 20K clicks on my local CL for $1150 right now.  For what you shoot, a 7D isn't necessary IMO - if you go with APS-C, get a T3i (same sensor as 7D), and perhaps an 18-135mm lens. That plus the 50/1.8 for portraits. If you get an xxxD, factor in buying SD cards to replace your CF cards.

But I still think keep your 5DII. The 24-105 is about the most versatile lens you can get on FF (arguably the 28-300L is more versatile, but it's heavy and expensive). 

Used 5Dc and 24-105 is another option.

7969
EOS Bodies - For Stills / Re: Only 1 lens
« on: December 10, 2012, 08:33:47 PM »
I'd keep the 5DII, sell both lenses and the 580, get a used 24-105L, a used 430 flash, and a used 50/1.8 II. I think that could net you $1500 and leave you with a very good kit for landscapes and portraits.

7970
Canon General / Re: What real Pros shoot...
« on: December 10, 2012, 03:46:33 PM »
Quite right, the Army hasn't used canons for over 100 years........ ::)

But use of the canon is still quite popular at weddings, in the key of DO.

7971
Below are a pair of 100% crops from shots at ISO 3200, one from the 1D X and one from the 7D.  I wonder which is which?   ::)

I could guess because I know crappy 18mp iso performance :-p ... but as written above, downsize that to forum web size (like 800px wide) and ask again... that's why I say iso performance has to be considered in relation to final output size, though I admit I'm a pixel peeper and have a hard time convincing myself.

Ok...how about now, with the original full images downsized?  I know that I can certainly tell them apart, even at 800x533.

7972
3. Thinking of moving objects(my daughter), I set my camera to AI SERVO, used all AF points, turned off IS and snapped away.  How would the focus on the 6D compare to this type of situation?  I would hope it would be better?  BTW, this was manually pressing the shutter button, not using burst.

The 7D will be better, IMO.  Higher density of AF points and all cross-type AF points both mean better AI Servo performance. 

5. Is using LR to clean up noise an acceptable practice?  Does anybody really care if they like the picture?  Most people that look at my photos(all but one really) don't even notice things like bad shadows, noise, sharpness, etc..

7.  Again, the sharpness in my images are also improved in LR.  And again, I ask, is it acceptable practice to use PP for things like this?

Of course.  All's fair in love, war, and post-processing.  Well, almost all - some photography contests restrict the amount/type of PP you can do, but NR is pretty much always fine.

6. As for the "advantage" of a crop sensor.  Don't take my words too seriously :)  I just meant that I get 1.6x vs. FF.  Call that a pro, con, whatever.  If I take a picture at 200mm with a 7D vs. FF, am I really getting a "closer" picture? 

You're not getting a closer picture.  A 200mm lens projects a subject on the focal plane at a given size, regardless of the sensor.  But as pointed out, current APS-C sensors generally have a higher pixel density than current FF sensors - that means more pixels on target with APS-C.  Whether that's a benefit for you depends on your output.  Comparing a 7D image to a 6D image cropped to the field of view of an APS-C sensor, the image quality will be at least equivalent, the 6D may be slightly better...but it will be a 7.8 MP image vs. an 18 MP image.  8 MP is sufficient for web, prints up to about 12x18", etc.  If you don't need to crop the image, the 6D will offer substantially better IQ.

9.  I noticed someone mention the 6D will easily beat out the 7D in low light.  Thinking about that, I like to take pictures without flash whenever I can.  I like the natural lighting better.  I think the 6D is much better for this scenario.

10.  Someone mentioned the noise when taking bird photos.  I agree 100%, the noise is really noticeable.  If you look at bird pics on 500px, flikr, etc... they are so clean, I often wonder if I'm missing something.  I hate to say it, but I'm pretty anal about noise.

The 6D (any FF sensor) gathers more total light - that means less noise at high ISO. I think my 1D X is about 2 stops better than my 7D, the 6D is likely at least 1.5 stops better.  Combined with a faster lens, that can make a big difference (provided you have enough DoF).

Of course, tomorrow I might change my mind and want to buy the 5D3 :D  I'm sure you all know how that goes  :P

As a general purpose camera, I think the 5DIII is a much better choice than the 6D.  I believe that you'll find the 7D to 6D to be a step up in image quality, but step down in AF performance for moving subjects and in build quality.  A 5DIII would be a step up across the board.

7973
So, with the same lens on each body and iso noise not being limiting...
Unfortunately, my experience with the 7D in environments where/when I commonly shoot birds is that ISO noise often is limiting, in particular for the high shutter speed often necessary.

For me (on 60d) the iso noise limit is in my head, that's the annoyance - next to exposure and framing I think about shutter speed/noise tradeoff all the time - either I get less keeper because of camera/motion blur, or the shots are crappy because of too much noise or too shallow dof.

Noise is not limiting when looking back at good shots, but few people state how many shots and opportunities they lost for a good one. That's why I'm really looking forward to a ff sensor. Realistically you can use higher iso even on crop when the final output size is not 100%, but for pixel-level 18mp iso800 is the absolute max that at least gives some air for postprocessing.

Below are a pair of 100% crops from shots at ISO 3200, one from the 1D X and one from the 7D.  I wonder which is which?   ::)

7974
Lenses / Re: 100mm 2.8L vs 135mm 2.0L
« on: December 10, 2012, 01:26:33 PM »
Edit; Neuro beat me by a second.

It was a full minute, actually.   :P

7975
Lenses / Re: 100mm 2.8L vs 135mm 2.0L
« on: December 10, 2012, 01:23:12 PM »
Everyone here always says the non-L macro is identical in sharpness to the L version. I've never seen any real evidence to this.

This.  Or compare this vs. this

7976
Lenses / Re: Problem with EF-S 10-22mm Image Softness
« on: December 10, 2012, 01:20:21 PM »
Asymmetrical loss of sharpness is usually due to decentering of one (or more) lens elements.  Canon can certainly correct the problem, not sure of the cost (depends on the severity), but figure $200 more or less.

7977
So, with the same lens on each body and iso noise not being limiting...

Unfortunately, my experience with the 7D in environments where/when I commonly shoot birds is that ISO noise often is limiting, in particular for the high shutter speed often necessary. 

7978
weather-sealed 35 mm lenses

Short answer: there aren't any.  Neither the Canon nor the Sigma are sealed lenses.  If you require a sealed lens at 35mm, you need to look at a zoom (16-35 II, 24-70 I or II) but then you're going to f/2.8.

Optically, the new Sigma 35/1.4 is better than the Canon 35L.

7979
Lenses / Re: What's your dream lens
« on: December 10, 2012, 10:54:26 AM »
EF 200 2.0L USM IS (in black)

Blasphemy!

7980
Lenses / Re: Sigma 35mm f/1.4 vs Canon 35mm f/1.4
« on: December 10, 2012, 10:53:33 AM »
There was a new Canon 35/1.4 patent some time ago. As I've pointed out before, every L-series prime at 100mm and under has been updated or newly released since 2006, except the 35L.  I'm hoping the Sigma release spurs Canon into releasing a 35L II - personally, I'm most interested in the weather sealing.
Technically the current Canon 35L is not fully weather sealed like most other L lenses so the Sigma is no worse off. Unless Canon changes this for a new 35, the Sigma will be just as good in theory. Also, do you really think Canon will put out a new 35mm since they just released the 35mm f/2 IS? Two 35's within a year would be rare.

Quite possible, as was pointed out they released two 24-70mm lenses almost concurrently.  The 35L is really due for an update, IMO.  If I didn't already have the 35L, I'd consider the Sigma.  As it is, I'm pleased with the 35L with the exception of the lack of weather sealing, which I presume would be a feature of a 35L II.  I'll keep waiting...

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