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01-08-2013, 02:43 PM   #76
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QuoteOriginally posted by Ben_Edict Quote
Then simply chose the appropriate lenses on both systems and here you go.

Ben
And sometimes, if I'm explaining my choices online, I'll use 'equivalent' numbers to explain them.

01-08-2013, 02:51 PM   #77
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QuoteOriginally posted by Ash Quote
Yes, but then we'd have to return to the inability to chimp, and work without a histogram, and have to scan images/negatives (which degrades IQ), and spend more on film and processing, and not be able to shoot 7fps, and, well you get the idea.
Occassionally when shooting the MZ5n I do chimp. Totally ineffective however.
01-08-2013, 03:22 PM - 1 Like   #78
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QuoteOriginally posted by Ben_Edict Quote
No, that is wrong and part of the misconception behind many (not all) statements related to the "equivalency modell".

The light "wasted" outside the sensor area does not contribute to the brightness of the image area ON the sensor, it is simply part of the lens' image circle, that will not be recorded as it is outside the sensor's boundaries.
I don't see what's wrong in what I wrote, because we are both saying the same thing. As the area of an APS-C sensor is (approx) half of the FF sensor, a APS-C sensor collect half the light when both use the same exposure settings. Of cource both images are exposed the same, but the APS-C image use half as many photons to create the image.
01-08-2013, 03:23 PM   #79
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QuoteOriginally posted by redrockcoulee Quote
Occassionally when shooting the MZ5n I do chimp. Totally ineffective however.
Haha!

01-08-2013, 08:42 PM   #80
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QuoteOriginally posted by Rondec Quote
I think these sorts of discussions are a little silly. Basically, if I take a photo with a 135 mm lens at f2.8 and iso 100 on APS-C, I will have the same photo (roughly) as if I took the same photo with a 200mm lens at f2.8 and iso 100 on a full frame camera, but with one more stop of depth of field.
Make that '200mm lens at f4.2 and ISO 225 on a full frame camera' and even the depth of field and the shutter speed would be roughly the same.

I don't find these discussions silly at all. How else would you be able to weigh your options considering different formats?

Last edited by Ikarus; 01-08-2013 at 08:48 PM.
01-08-2013, 09:43 PM - 1 Like   #81
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In all my readings of comparing lens focal length equivalents with the different LF formats and MF and 35mm there is discussions if you use the short side or the long side or the diagonal because each of those formats have different aspect rations but have never read anything with aperture or depth of field equivalents. Some of these articles are 60 years old and some are current. And it is not as if some people who shoot MF or LF do not shoot with shallow depth of field either. Even the comments I have read on several Hasselblad forums in regards to the crop of their digital does not discuss this but which lens works as what instead.
01-08-2013, 11:04 PM - 1 Like   #82
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The individual cell (pixel) on APS-C sensor is recording amount of light reflected from the part of object that was transferred (the part of object) by lens and has nothing to do with size of sensor.
The TTL sensor NOT the size of the APS-C sensor defines exposure based on measuring mode (MS/CW/Spot), otherwise after the every half/way push of the shutter release button we would make a mirror jump. So the TTL output function adjusted such way that we have the appropriate exposure of the APS-C/FF sensor. I agree with statements that size of the APS-C sensor defines FOV and DoF by changing magnification/the actual length of focus.


QuoteOriginally posted by Fogel70 Quote
Or do you think that if you put one small and one large bucket out in the rain, that both of them will collect the same amount of water for a given time?
By considering my statement above, this analogy should be as follow: if we take two trays the big one and small one and load them with the identical size of the small caps and put these trays out in the rain the each cap collects the same amount of rain no matter to what tray(big or small) it belongs. The total amount of water collected in the big tray will be be more than one collected by small tray. However, collected total amount of water is representing amount of information NOT intensity (exposure) - the rain drops were falling with same regularity (frequency.) Now, if we put a screen that reflects some of the all rain drops over half of the big tray and over half of small tray the relative difference of amount of water between open and covered by screens areas of trays (exposure difference) will be identical for big and small trays.

Cheers.

Last edited by pavpen; 01-08-2013 at 11:19 PM.
01-08-2013, 11:43 PM   #83
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QuoteOriginally posted by Fogel70 Quote
I don't see what's wrong in what I wrote, because we are both saying the same thing. As the area of an APS-C sensor is (approx) half of the FF sensor, a APS-C sensor collect half the light when both use the same exposure settings. Of cource both images are exposed the same, but the APS-C image use half as many photons to create the image.
But if you go back to film (we remember what that is don't we) the exposure is based upon a light density, for lack of a better definition, I.e. how much total light per unit area falls upon the film. Changing the image circle (the true difference between FF and APS C ) does not change the light density. Image brightness is NOT based upon the total light, but the density per unit area, and this is ultimately only a function of how much light enters a frame through the front,

Draw yourself a simple lens and the two format sizes with the APS-C sensor placed inside the FF sensor. You will see that for an image, the cropping the middle only changes how much of a projected image is recorded. Now make the lens twice as big, you will see that more light is gathered.

When you consider using a cropped sensor lens, all that happens is that light which would not hit the sensor is absorbed in the lens baffles internally, where as a FF lens puts this additional light into the mirror box, where it is either absorbed ( if the mirror box is well designed) or reflected all around off all the mechanisms, leading to reduced contrast and flare

01-09-2013, 12:02 AM   #84
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QuoteOriginally posted by Lowell Goudge Quote
But if you go back to film (we remember what that is don't we) the exposure is based upon a light density, for lack of a better definition, I.e. how much total light per unit area falls upon the film. Changing the image circle (the true difference between FF and APS C ) does not change the light density. Image brightness is NOT based upon the total light, but the density per unit area, and this is ultimately only a function of how much light enters a frame through the front,

Draw yourself a simple lens and the two format sizes with the APS-C sensor placed inside the FF sensor. You will see that for an image, the cropping the middle only changes how much of a projected image is recorded. Now make the lens twice as big, you will see that more light is gathered.

When you consider using a cropped sensor lens, all that happens is that light which would not hit the sensor is absorbed in the lens baffles internally, where as a FF lens puts this additional light into the mirror box, where it is either absorbed ( if the mirror box is well designed) or reflected all around off all the mechanisms, leading to reduced contrast and flare
Yes, I know this. but wasn't it just what I wrote?

A smaller sensor capture less light because it is smaller, not because intensity of light is lower. "Area of sensor" x "intensity of light" = total amount of light captured by the sensor.
01-09-2013, 04:15 AM   #85
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QuoteOriginally posted by Ikarus Quote
Make that '200mm lens at f4.2 and ISO 225 on a full frame camera' and even the depth of field and the shutter speed would be roughly the same.

I don't find these discussions silly at all. How else would you be able to weigh your options considering different formats?
It's not hard at all. You choose a format based on features, cost, and size. Depth of field, for me, just isn't an important factor when making a decision. I just see these discussions a lot more with APS-C and full frame 35mm, seldom with medium format and full frame 35mm, for instance. I suppose it has a lot to do with familiarity with 35mm format going back to film days, but for younger shooters, who began in digital, the comparisons have little value, since they didn't shoot 35mm in the first place.
01-09-2013, 05:07 AM   #86
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But there is many other formats today. Nikon 1, Pentax Q, Canon M, Sony NEX all use different sensor size, which can make it difficult to choose the "best one", if you don't know what difference sensor size do.
01-09-2013, 07:33 AM   #87
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QuoteOriginally posted by Fogel70 Quote
But there is many other formats today. Nikon 1, Pentax Q, Canon M, Sony NEX all use different sensor size, which can make it difficult to choose the "best one", if you don't know what difference sensor size do.
Yes and no. If you are using a Q, what does it mean that you will get "five stops more depth of field" than full frame? I don't really know. All it really tells me is that there is a lot of depth of field. The field of view adjustment means more to me, but features and iso performance tend to be the reasons for choosing a particular small format camera.
01-09-2013, 12:52 PM   #88
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QuoteOriginally posted by Rondec Quote
for younger shooters, who began in digital, the comparisons have little value, since they didn't shoot 35mm in the first place.
I think you're underestimating the younger shooters. It's not like 35mm shots aren't already readily available to them for reference and with the advent of more affordable full-frame DSLRs from other manufacturers there is only going to be more of that. I can see how a young owner of a brand-spanking new K-01 with a DA 40/2.8 might find himself using that lens wide open most of the time in order to approach the subject/background separation he wants, without actually ever getting anywhere close. In that sense, the comparison to a full-frame camera with a 60mm f/4.2 is rather relevant, since it tells you that a very humble and dirt-cheap Helios 44 58mm f/2 would easily do the job.
01-09-2013, 04:34 PM   #89
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QuoteOriginally posted by Fogel70 Quote
Yes, I know this. but wasn't it just what I wrote?

A smaller sensor capture less light because it is smaller, not because intensity of light is lower. "Area of sensor" x "intensity of light" = total amount of light captured by the sensor.
But note, the "light" captured by the crop is not just less total light, that I think we agree, but the crop does not reduce light relevant to the image information within the crop. The light external to the cropped area is containing information that is not relevant to the image within the crop, so no matter what you do with that light, it does noting to either increase the light per unit area (i.e. flux) or reduce the exposure time but if you increase the diameter of the objective/front element, that gathers more total light including what IS relevant to the image within the crop. Consider two objectives of the same focal length but different diameters. Draw the lines of light form a subject to the image through the two lenses. Now note that light reflected from the subject can pass by the area of capture of a small lens, but be captured by the large lens and still focused on the image of the subject on the sensor. Bigger front elements can be seen to put more light per unit area onto any point of the sensor and therefore it is aperture/ objective diameter that controls light per unit area not the image circle of the lens, which really only controls field of view
01-10-2013, 01:18 AM   #90
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QuoteOriginally posted by Lowell Goudge Quote
But note, the "light" captured by the crop is not just less total light, that I think we agree, but the crop does not reduce light relevant to the image information within the crop. The light external to the cropped area is containing information that is not relevant to the image within the crop, so no matter what you do with that light, it does noting to either increase the light per unit area (i.e. flux) or reduce the exposure time but if you increase the diameter of the objective/front element, that gathers more total light including what IS relevant to the image within the crop.
Yep, but it is possible to create a "inverted TC" to make a FF lens into a APS-C lens, so that a APS-C sensor will capture all the light that is used for FF. And this double the light per unit area on the APS-C sensor.

QuoteQuote:
Consider two objectives of the same focal length but different diameters. Draw the lines of light form a subject to the image through the two lenses. Now note that light reflected from the subject can pass by the area of capture of a small lens, but be captured by the large lens and still focused on the image of the subject on the sensor. Bigger front elements can be seen to put more light per unit area onto any point of the sensor and therefore it is aperture/ objective diameter that controls light per unit area not the image circle of the lens, which really only controls field of view
Yes, this is simple physics.

But as FOV is one of the most important features of a lens, and is IMO more relevant than light per unit area captured by the sensors.
if you want to capture the same image with different sensor size you need the same FOV. By using same FOV you will also need the same aperture diameter to create the same DOF independent of sensor size. So when using different sensor size to create the same image the smaller sensor has to capture more light per unit area.

50mm at f/4 on FF create the same FOV and DOF as 25mm f/2 on m43. And image noise will be comparable on them as both capture the same total amount of light using the same shutter speed.
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