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07-11-2015, 02:24 PM   #16
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QuoteOriginally posted by normhead Quote
APS_c------------------- FF

IS0 100...................ISO 200 - DR and noise are equivalent
1/100s....................1/100s - shutter speed is equivalent
ƒ2.8........................ƒ4 - total light used by the sensor to create the image and DoF are equivalent..
True*
And what you choose of this is highly subjective and will change from shot to shot. Hence there's no universal law of equivalence to be had except for lens speed. ie 1.4 = 1.4. You can't get away from that one. It is also the industry standard since the invention of photography. For a reason.

*(except that ponit 3 above is only true as long as you are within the subject magnification available on FF; APS has larger magnification and hence thinner minimum DOF at the same aperture and angle of view for comparable lenses).

---------- Post added 07-11-15 at 11:29 PM ----------

QuoteOriginally posted by starbase218 Quote
Clackers, I told you his before: assuming similar sensor technology, you can bump up the ISO on the FF sensor by 1 stop compared to the APS-C sensor and have similar DR/noise. In fact, the ability to go to higher ISOs without so much of the penalties is why some people want to go to fullframe in the first place.

Lenses doesn't get equivalent by cranking up the ISO. ISO is a property of the sensor, not the lens. Cranking up ISO or not is a subjective decision. Which one of the parametres of reciprocity you use while using different formats is totally subjective. Hence you cannot derive some objective principles from it. That is, if you're a photographer.

If you do follow the "principle of eqiuvalence" you are loosing most the advantage of FF. You been better stickin to a smaller format.

I've used different formats and I don't crank up the ISO unless I have to.


Last edited by Pål Jensen; 07-11-2015 at 02:34 PM.
07-11-2015, 02:46 PM - 1 Like   #17
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QuoteOriginally posted by Pål Jensen Quote
Lenses doesn't get equivalent by cranking up the ISO.
I'm not saying that.

QuoteOriginally posted by Pål Jensen Quote
If you do follow the "principle of eqiuvalence" you are loosing most the advantage of FF.
I know. I'm not saying that either.

QuoteOriginally posted by Pål Jensen Quote
Which one of the parametres of reciprocity you use while using different formats is totally subjective. Hence you cannot derive some objective principles from it.
So you're saying the article on DPreview is nonsense?

QuoteOriginally posted by Pål Jensen Quote
That is, if you're a photographer.
Well, I try:

Last edited by starbase218; 07-11-2015 at 03:02 PM.
07-11-2015, 03:11 PM   #18
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QuoteQuote:
So you're saying the article on DPreview is nonsense?
Just misleading, and some of the conclusions don't match the data. From a brief glance it seems to be really unclear evaluation of their images, clouded by using too many systems making it harder to understand their point, followed by framing the argument in an unclear manner open to mis-interpretation. Apart from that it's a gem.

I mean, if you know your way around this stuff, you can see how this stuff supports your points, if you don't, I don't see how this would point you in the right direction.

The noise comparison images showing the differences between the formats is good if you look at the images and don't let the text tell you what to think about them.

But hey, we make those kinds of comparisons using the test charts at Imaging Resources all the time. Then I get to choose what two cameras to compare. The cameras they chose for their little demo, I'm not interested in any of them. It makes it a lot harder to read the article.

Last edited by normhead; 07-11-2015 at 03:27 PM.
07-11-2015, 03:16 PM   #19
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QuoteOriginally posted by normhead Quote
APS_c------------------- FF

IS0 100...................ISO 200 - DR and noise are equivalent
1/100s....................1/100s - shutter speed is equivalent
ƒ2.8........................ƒ4 - total light used by the sensor to create the image and DoF are equivalent.

These images are roughly equivalent (ignoring the 1/3 stop) . There is simply no FF advantage.
wrong, as usual you failed to equalize the fov... stop putting ff lens on crop, and calling it equal! it's not!

why do crop people keep getting this confused?

i'll cross-post, yet again:

"Another situation to be considered is when there is enough light to achieve the desired DOF at base ISO without adverse affects due to motion. For example:

• 6D at 50mm, f/5.6, 1/200, ISO 100
• D7100 at 33mm, f/3.5, 1/500, ISO 100
• 60D at 31mm, f/3.5, 1/500, ISO 100
• EM5 at 25mm, f/2.8, 1/800, ISO 100

The IQ advantage, all else equal, will go to the larger sensor systems in this case since they will record more total light as well as usually put more pixels on the scene. On the other hand, the IQ differential in this situation is often going to be the least significant in that all systems are often well past "good enough" for most purposes.

Next up is when noise and/or a more shallow DOF matters more than captured detail:

• 6D at 50mm, f/1.4, 1/200, ISO 1600
• D7100 at 33mm, f/1.4, 1/200, ISO 1600
• 60D at 31mm, f/1.4, 1/200, ISO 1600
• EM5 at 25mm, f/1.4, 1/200, ISO 1600

The same f-ratio on all systems results in wider aperture diameters for the larger sensor systems (50mm / 1.4 = 36mm, 33mm / 1.4 = 24mm, 31mm / 1.4 = 22mm, 25mm / 1.4 = 18mm) which results in a more shallow DOF for the larger sensor systems as well as more total light falling on the sensor for the larger sensor systems, resulting in less noise for equally efficient sensors (or, at least, close to equally efficient).

However, it is more than likely that at such wide apertures, the lens will suffer greater aberrations for the larger sensor systems. Thus, even for the portions of the scene within the DOF, we may find that the smaller sensor system records a more detailed photo (of course, this has to be taken on a lens-by-lens basis). In any case, we would only compare the same f-ratio on different formats if DOF and/or noise mattered more than sharpness."

Equivalence

07-11-2015, 04:29 PM   #20
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So I can use the DoF table.....
Nikon D800 at ƒ4 and 50mm at 10 feet away has a DoF 8' 8.9 inches to 11'8" approx. 3 feet.
A nikon D7000 at 33mm @ ƒ2.8.. and 10 feet away has a DoF of 8' 7.8 to 11' 10" approximately 3 feet.

SO roughly the same.

That's almost a 1 stop light advantage for the APS_c camera if you keep DOF the same.
The faster ƒ-stop you can shoot for on APS-c makes up for the higher ISO you can use on FF which equalizes the noise.
So how does that fit into your theory?

I've never really trusted these DoF calculators but we really need to get you on to some way to check your assumptions.

http://www.dofmaster.com/doftable.html

Do you not understand that the goal here is to equalize DoF, and then see how everything else lines up? If you don't equalize DoF, everything else is nonsense. And that has been the ploy of Full Frame propagandists... if you don't equalize DoF, you can argue all kinds of crazy stuff, that is all smoke and mirrors.

QuoteQuote:
wrong, as usual you failed to equalize the fov... stop putting ff lens on crop, and calling it equal! it's not!
So, is the DoF table wrong too? Everybody is wrong but you? I see how this works.

Does the DoF table also put the "ff lens on crop". Well at least if I'm wrong, I'm in the company of some very smart wrong people.

Last edited by normhead; 07-12-2015 at 05:29 AM.
07-12-2015, 10:45 AM   #21
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One thing though: we've been talking about things like equivalence, magnification, etc etc. in a really theoretical way. I used to think that if you know enough about photography, you can become a better photographer. Then about 3 years ago I went on a photo trip to Iceland, with a group. We were accompanied by a professional photographer who was also our tour guide. She was a great person btw, and she motivated all of us. But the thing is, I knew more about photography than her. I knew what hyperfocal distance was, she didn't. Of course she understood the concept when I explained it to her, but apparently she hadn't applied it yet. There were some other things she didn't know and I did, and I think she also may not know all the things like magnification, how equivalence works (or doesn't), etc etc. Nevertheless her photos were so much better than mine. She noticed things that I didn't. The trick - at least for me - is to not dive into theory, into technical details, but instead to notice what's around me and what inspires me. Which is sometimes hard as I'm kind of a technical person, or at least I used to be.

Anyway, I'm just saying, maybe technical correctness etc. isn't so important as we make it. It can be nice to know, but I think you can be a great photographer without that knowledge as well.
07-12-2015, 10:54 AM   #22
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If you're spending this much time on the technical, you're probably not doing the practical.... and you're right, I've seen some technical dimwits who always saw a great angle and got a great image. Being a tech genius in photography makes you pretty much useless, if that's all you've got. Todays shooting. Shoot as much as you can every day... type on the internet when you're too tired, hot and sweaty to do anything else.

K-3 - DA 18-135 -

My grandson is back in Alberta, Tess has gone off to visit her son, and grand niece and grand nephew, I'm just hanging out down at the old swimming hole.

This is what happens when you think you've got the timer set to 12 seconds, but it's set to 2 seconds... you aren't sitting in your chair when the shutter goes.



Tripper diving...


Tia diving..


Misty lost two sticks and a ball, when she gets tired she goes and hides her toy, but then she never goes and gets it when she's ready to go again... see that smile on her face, she saying " I put my toys someplace you'll never find them, but it sure is fun watching you look. "


Blueberries are ripe in some places, but not here...


There's always something happening with the flowers.


07-12-2015, 10:58 AM   #23
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QuoteOriginally posted by normhead Quote
So I can use the DoF table.....
Nikon D800 at ƒ4 and 50mm at 10 feet away has a DoF 8' 8.9 inches to 11'8" approx. 3 feet.
A nikon D7000 at 33mm @ ƒ2.8.. and 10 feet away has a DoF of 8' 7.8 to 11' 10" approximately 3 feet.
everything that i've posted references equal dof.

you aren't accounting for shutter speed and iso with a dof calculator, so it's not equivalence.

QuoteOriginally posted by starbase218 Quote
I knew what hyperfocal distance was, she didn't. Of course she understood the concept when I explained it to her, but apparently she hadn't applied it yet.
she may not have needed to calculate it: "Perhaps the best way to optimize your focusing distance is visually." Understanding Your Camera’s Hyperfocal Distance ...which can be done easily with a good evf camera.


Last edited by osv; 07-12-2015 at 11:10 AM.
07-12-2015, 11:03 AM   #24
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QuoteOriginally posted by osv Quote
that's not equivalence, because it doesn't take fov into account.

same failed logic as before
I used 50mm on FF and 33 mm on APS_c, how else would you take FoV into account?

Why don't you show us a calculation that does take FoV into account if you're such a genius.
07-12-2015, 11:15 AM   #25
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QuoteOriginally posted by normhead Quote
I used 50mm on FF and 33 mm on APS_c, how else would you take FoV into account?

Why don't you show us a calculation that does take FoV into account if you're such a genius.
sorry, i corrected it already.

like those summer pics, btw :-)
07-12-2015, 01:32 PM - 1 Like   #26
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I love these equivalence threads ...
07-12-2015, 01:45 PM   #27
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QuoteOriginally posted by osv Quote
sorry, i corrected it already.

like those summer pics, btw :-)
You've corrected nothing.

And glad you like the pics.

Last edited by normhead; 07-12-2015 at 02:37 PM.
07-12-2015, 04:24 PM   #28
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QuoteOriginally posted by osv Quote
she may not have needed to calculate it: "Perhaps the best way to optimize your focusing distance is visually." Understanding Your Camera’s Hyperfocal Distance ...which can be done easily with a good evf camera.
She had a Nikon D700. Tried it once or twice btw. Focusing was lightning fast with the lens (I think it was the 24-70) she had. Kind of made me envious.
07-12-2015, 05:02 PM   #29
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QuoteOriginally posted by clackers Quote
Incorrect.

The FF shot at f4.2 is now a stop darker, with all the ramifications.

Why do people still buy into this?
Focal Ratio is a measure of the ratio of the focal length divided by the aperture of the glass.

The amount of light captured (brightness) depends on the size of the sensor relative to the the exit pupil of the lens. If you don't believe this then experiment with a magnifying glass, making large and small projections on a piece of paper, and you will find that the smaller the projection, the brighter the image.

DOF does change with format (FOV) and is due to the 1.5x extra magnification that a standard print or monitor presents. People say "oh, it's still a 50mm lens etc" but they overlook the extra TELECONVERTER EFFECT of the output medium.. which, combined with change in FOV, changes the DOF.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

I've uploaded a couple of screen grabs from LR to show (as closely as my sloppy methodology allows) how a 24mm lens @F2.8 is a "match" for a 36mm lens @f4-4.5.

This is a Tamron 24-70 F2.8 VC lens on a D810 in FF Mode(36mm) and 1.5x Crop Mode(24mm)

They look close apart from the exposure time. The light changed a bit and it's windy (shots taken about 20 minutes ago). I believe that f/4 @36mm is a closer match however.

The close-up 100% shows the relative sizes of the OOF specular highlights to the subject. They look close in each image.
Attached Images
     

Last edited by bossa; 07-12-2015 at 05:52 PM.
07-12-2015, 10:25 PM   #30
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QuoteOriginally posted by starbase218 Quote
Clackers, I told you his before: assuming similar sensor technology, you can bump up the ISO on the FF sensor by 1 stop compared to the APS-C sensor and have similar DR/noise. In fact, the ability to go to higher ISOs without so much of the penalties is why some people want to go to fullframe in the first place..

And you're still incorrect, Starbase.


Aperture is a function of the lens, not the sensor size.


ISO performance is a function of the size of pixels ("water wells"), the electronics, and the number of pixels used to resample (software noise reduction), not sensor size.


QuoteOriginally posted by starbase218 Quote

edit: you may also want to read this: What is equivalence and why should I care?: Digital Photography Review
edit 2: actually, topicstarter may also want to read this article.

The article is way more tentative than you, carefully stating: "This is why we tend to state that, although equivalence can be used as a guide to low light performance, it can't be used to completely predict the differences."


This is because four different cameras are being compared. How is that 'equivalent'?


I'm telling you, if you take a cropped shot with an A7 or 1D or 810 or whatever, the dynamic range in the cropped section does not suddenly decrease or its noise level increase!


Once you make the electronics and numbers of postprocessing pixels "equivalent", the shots become that way too.


Angle of view is the only thing that changes between formats.

Last edited by clackers; 07-12-2015 at 11:26 PM.
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