January 31, 2015, 12:50:48 PM

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Messages - Sporgon

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1

You can simply test your software. Switch to manual mode and take a photo of some dark objects before a dominant white wall and expose like the camera would do (make the white wall grey). Then expose to the right and remember how many EV you increased the exposure. E.g. 1/100s camera exposure vs 1/25s ETTR exposure = +2EV. Then use the RAW files and convert them with your software and apply -2EV exposure to the second picture. Now they should have EXACTLY the same color properties but the ETTR picture should have less noise. If not, your software is not up to that specific task.




At the end of the day the goal is to take a picture and to expose for that specific subject and the sensor noise may actually be low enough that you are satisfied with the exposure suggested by the spot metering of the camera. In that case you can directly use the camera JPEGs and be fine. Heavy postprocessing is only for low volume activities or people with too much time.

What a load of rubbish ! You have underexposed the White wall in the first place due to the failings of your camera (reflective ) meter ! Your 'ETTR' is only to get back to the correct exposure anyway.

I've said it many times; those interested in learning photography should get themselves an incident light meter and start to get to grips with exposure. (And the fact someone posts here suggests they are interested).

As for 'the' spot meter reading, this is another exposure error give away. The whole idea of a spot meter is to take multiple readings. One spot meter reading is likely as not to be highly inaccurate.


2
EOS Bodies / Re: POLL: How many mp do you want anyway?
« on: Today at 06:03:28 AM »
When I would scan my Velvia on a good film scanner I would get files that are about 30 MP in size.  I have always felt that was about the best that I could get out of the my film with a 35mm slide.  Still, modern lenses can out resolve my best film age lenses, so I would love to see what the files would look like from a 50 MP sensor.

How much of that 30 mp is emulsion grain ?

3
EOS Bodies / Re: Appreciation post
« on: Today at 04:34:15 AM »
I just got some old 8mm video reel converted to digital (taken on a Canon 514XL in 1978).
While its content is priceless I was struck by how incredible the gear we have today is in comparison.

Back to 2015 and the video from my 1Dx is stunning. Every time I put on a different Canon lens on my body I think - actually this is an incredible lens too! So thank you to all the engineers and scientists who have contributed to gifting us insanely powerful photography equipment.

Some people are waiting for the never to arrive tomorrow to be satisfied - incremental updates in dynamic range come to mind!

I seem to be having a very insighful and mindful morning :)

I have drawers full of medium format 6x6 and 6x7 negatives and transparencies as well as a number of 5x4 transparencies. All in great nick; I'll scan some and post a few on CR some day.

I recon that FF is now comfortably ahead of 6x7 and my stitches are ahead of 5x4.

4
And then the blacks:

To summarise, we have lost saturation in the lighter blue and have gained nothing in the smoothness of the blacks.

Thanks for taking the time to do such an elaborate illustration of your point.  However, maybe you don't see gain because your sensor didn't produce noise in the blacks in the first place.  Is it possible to repeat your experiment with a much higher ISO? (I could try it myself, but if I post the results my crop sensor will spark DR arguments I fear, so I'll refrain).

Honestly, it wasn't that elaborate. It took all of ten minutes !

You are right about not producing noise in the blacks in the first place, but that is the issue with so many of these discussions regarding Canon 'IQ'.

If the exposure was correct with high ISO, and the EV range was within the scope of the sensor, I don't see it would make any difference to the principle here.

5

unless I changed the settings so much that then the preview looked dramatically different than the subject.


Welcome to raw RAW !

6
I think the tonality "issue" when trying to lower exposure of a overexposed sky is due to the fact that the closer we are to clipping all the channels, the harder it is for an individual channel to stick out and be visibly dominant. When we, in post, drag our sliders down, we are stuck with values that's perceived as closer to a "tinted light grey" (240 240 255), than a "subtle blue" (170 170 185).

How about that as a thought?

I think it has something to do with blue being the 'weakest' or 'darkest' wavelength of light, and the camera processor is applying more amplification to blue.

Certainly red and green are not as effected by overexposure, but it is there if you are extreme enough.

7
I haven't used a color picker to check saturation, I judged by looking at the pictures in the second set. Anyway, the brick wall does not look like it has identical exposure in both pictures.
I am wondering how the OP has done his adjustments. I think that using sliders in any software is not going to produce a linear shift of the values. I haven't tested it yet, but the best bet would be to use the curve tool and shift linearly everything.

They were not identical exposures, the second was two full stops over, then reduced two stops in DPP before converting to 16 bit TIFF.

I don't use 'sliders' to alter an image, this was tweaked in curves to balance the appearance. A very minor adjustment but I can't remember now, and these files are deleted anyway.

Using a small amount of ETTR is well established for assisting in a number of circumstances, and often something that I would do if faced with a single exposure shot of something in high contrast. However my point was made because of the LL article advising that the 'correct' exposure for a black cat in a coal hole is to expose the raw as virtually white, even given the date that this was produced.


8
Software & Accessories / Re: Photostitch ain't perfect, or is it me?
« on: January 28, 2015, 11:30:57 AM »
Mr. Haines,
The thing that sort of surprised me is I did this shot with the TS-E 24 but shifting left, center, and right. I am totally on board with the perspective changing and curving straight lines as you rotate. But, since I had the tilt shift vertical (as close as I could tell) and was merely shifting and not rotating, I didn't think the seams would fail to line up. But, they did.
Tanispyre,
I was using a solid all metal tripod, a 6D and a TSE-24mm that's new to me, but purchased new 6 months ago from B&H.
I'll mess with it some more and see what happens next.
Thanks for all the advice!  :)

Irrespective of the software you're using, what you are finding is how not to shoot a pano. Be aware that if you are both straight on to your subject and in the middle you are going to find it much harder to get a satisfactory result. Add the fact that you're very close to your subject, the subject is a straight line and you've gone quite wide; you'll need a fair bit of manual tweaking with any program.

My advice: don't try and do this type of thing as a pano.

9
Lenses / Re: Canon prime rumors? 50mm f1.4, 85mm f1.8 and 100mm f2
« on: January 28, 2015, 09:15:12 AM »
I doubt Canon will produce an updated version of both the 85 and the 100. Of the two I'd be pretty sure they'd go for the 85.

Theoretically the 85/1.8 is designed primarily for portraiture, the 100/2 more for sports etc. The 85 is less corrected for CA and produces a nicer bokeh - at least if you can see any difference most of the time. This is why people complain more about purple fringing on the 85 more than the 100 yet despite this it is by far the most popular of the two.

I would guess that the delay in introducing the 50 and 85 is Canon are scratching their heads wondering how to produce a worthwhile update in optical quality, with IS, at a price  point where it is worth it for them to produce and the customer will buy. From f/2.8 the current 50 is a stellar performer across the frame, easily able to aquit itself on an upcoming 'high' mp camera. The 85 also. This wasn't the case with the predecessors of the new IS trio, so I think Canon were getting their ducks in a row on those focal lengths.

10
Thand any Pentax 67 LS lens can be shot via adapter  (full manual).

If you are talking about using old Pentax 6x7 lenses on a 645z you'll likely get a shock. No doubt fine for portraiture, but they were never the sharpest lenses on medium format. Highly regarded for portraiture, yes, but will be left wanting on the latest 50 mp DMF sensor.

11
I think that if you really need and/or want 50 mp then you have done the right thing, irrespective of what Canon do with a higher mp FF sensor. 50 mp on a FF size sensor is a total waste in my opinion.

Personally I prefer to stick with FF and stitch for the sort of work I do. It is so easy to stitch now, especially if you are using a lens who's entry pupil is close to the camera body. Obviously with your portrait work you cannot stitch.


12
Canon EF Prime Lenses / Re: Canon EF 50mm f/1.4 USM
« on: January 26, 2015, 03:28:18 PM »
I find that as long as you are quite close to subject and really nail the focus the EF 50/1.4 is useable at f/1.4

Canon 5DII + EF 50/1.4 @ f/1.4

Sleeping Piggies

13
Lenses / Re: I'm conflicted please help
« on: January 26, 2015, 01:31:47 PM »
My point is that in the uk the 500mm is £8000 the 400 is £1100 and most of the time can be found for <£800 if 20% reach one stop and IS is worth £7000 extra... By learning a little more about the subject and also learning some hunting/tracking skills and wearing camo your images will be better, your arms and body not as tired and your wallet will be a lot larger.

Most of the time to get enough DOF With birds you shoot higher than F5.6.

I would probably look at bigger, but the weight puts me off especially for a full days shooting.

Never mind that. Where are the pictures from your Amazonian expedition ?

14
EOS Bodies - For Stills / Re: Difference in image from APS-C to FF
« on: January 26, 2015, 10:47:58 AM »
Here's one big difference between APS-C & FF - the pixel density really brings out the flaws in lenses - check out the purple fringing in the 7DII vs. 1DsIII from the latest test on TDP - yikes:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=397&Camera=963&Sample=0&FLI=0&API=0&LensComp=397&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=0

Is that pixel density doing that or distance from the chart ? I presume these are shot on the same framing so the 7DII will be further away.

I think TDP is a very useful and well executed resource, but I'm not sure allowing direct comparisons between APS and FF reflects real world results.
I'm no optical expert, but I would think that the abberations would improve the closer you get towards infinity focus, so I would think it's the pixel density.  I noticed this same phenomenon with my fast lenses, particularly with the 24L II and 50L when I was shooting with a crop sensor.

Yikes ! Yet another point then, to add to my list of reasons to get hold of another 5D mark one.

15
EOS Bodies - For Stills / Re: Difference in image from APS-C to FF
« on: January 26, 2015, 10:30:48 AM »
Here's one big difference between APS-C & FF - the pixel density really brings out the flaws in lenses - check out the purple fringing in the 7DII vs. 1DsIII from the latest test on TDP - yikes:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=397&Camera=963&Sample=0&FLI=0&API=0&LensComp=397&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=0

Is that pixel density doing that or distance from the chart ? I presume these are shot on the same framing so the 7DII will be further away.

I think TDP is a very useful and well executed resource, but I'm not sure allowing direct comparisons between APS and FF reflects real world results.

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