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11-03-2014, 02:36 PM   #16
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wizzster, you succeeded in confusing me in an area where I don't get confused often

11-03-2014, 02:56 PM   #17
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I think the misinformation is that a lot of people think that they would have the same bokeh with a 35mm on aps-c as a 50mm on FF (if the 2 lenses have the same aperture). That is far away from reality, the only thing that would be aprox the same is FOV. A couple month ago i read a post from a nikon guy on a nikon forum complainig because he only could get the same bokeh from a 35mm 1.8 DX on his d7100 if he stop down 2 f stops a 50mm 1.8 on his d800. Sorry about my english...
11-03-2014, 03:06 PM   #18
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QuoteOriginally posted by Kerrowdown Quote
Welcome to the forum, you are not alone, crop factor discussions are recurring themes around here quite often.
Yes, welcome to the Pentax Forums!

Equivalency discussions are also big. You will be very busy.


Steve
11-04-2014, 12:10 PM   #19
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QuoteOriginally posted by flaviopetrone Quote
A lot of professional photographers use APS-C sensors instead of Full Frame because of the longest focal (1.5 x).
I don't understand why it is supposed that we are "losing" something.
I was using a point and shoot camera and a Samsung Galaxy S4 when I finally got the money for a DSLR, I gained a lot of quality, the possibility to totally customize my shots, to use amazing lenses and to post process RAW files.
I gained in every direction.
I think that the main part of this forum is not shooting Digital Full Frame too, but if someone swaps full frame for APS-C, this just means that they are swapping field of view for longer zoom.
Seriously, this kind of posts which is not starting with correct informations only confuse people.
I'm just trying to point out that a smaller sensor means a smaller field-of-view and not increased focal length. E.g. if you want to photograph birds, would you use a smaller sensor instead of a longer focal length lens ? Instantaneous reolution, which is equal to the pixel size divided by the focal length is not improved by having a smaller sensor (with less pixels). This is called IFOV and it is what determines the sharpness of the picture (in addition to lens quality).

Anyway, full frame sensors are becoming available and this discussion will become meaningless (I hope) !

---------- Post added 11-04-14 at 02:14 PM ----------

QuoteOriginally posted by Pablom Quote
wizzster, you succeeded in confusing me in an area where I don't get confused often
My apologies ! Think about it this way. Suppose you took the sensor in your DSLR and put tape over on half of it, so you only got half the field-of-view.
Is this the equivalent of doubling the focal length of your lens ? Could you double the distance from your subject and still get the same quality ?

No. Hope this helps.

11-04-2014, 12:23 PM   #20
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QuoteOriginally posted by wizzster Quote
I'm just trying to point out that a smaller sensor means a smaller field-of-view and not increased focal length. E.g. if you want to photograph birds, would you use a smaller sensor instead of a longer focal length lens ? Instantaneous reolution, which is equal to the pixel size divided by the focal length is not improved by having a smaller sensor (with less pixels). This is called IFOV and it is what determines the sharpness of the picture (in addition to lens quality).
If you need a great wall print, you are right. If you are in the other 99% people, you won't see any considerable difference, if not in your wallet.
11-04-2014, 12:59 PM   #21
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QuoteOriginally posted by flaviopetrone Quote
If you need a great wall print, you are right. If you are in the other 99% people, you won't see any considerable difference, if not in your wallet.
I still get great wall prints from my taped over sensor so I don't know what the fuss is about.
11-04-2014, 02:12 PM   #22
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QuoteOriginally posted by wizzster Quote
E.g. if you want to photograph birds, would you use a smaller sensor instead of a longer focal length lens ? Instantaneous reolution, which is equal to the pixel size divided by the focal length is not improved by having a smaller sensor (with less pixels).
But that's only if there weren't other factors as well, no?

What happens when comparing a smaller 12 MP sensor to an (older) FF sensor with only 8MP? You'd get the longer reach of the lens and more pixels. Or, more likely, what if the pixel count is equal on both?

Of course, there's a limit to the MP-race, as adding more pixels to an ever smaller sensor diminishes quality.
And I'm sure, that a FF 24MP will be better than the K3's equal amount. But would the difference in IQ be so grand, for me as a hobbyist, to justify spending thousands more on a FF camera and FF lenses with 1.5 times higher focal range?
Not even counting increased size and weight into it.

I think I do get your point, and so it is great when there are choices for everyone. Thankfully for Pentax' medium format and soon FF there will be a plenty of them. But for me as an enthusiast I feel like I got a good balance with an APS-C and it's crop factor.

Who'd want to lug a 900mm lens around to go birding with their 6x7, no matter the IQ?
11-04-2014, 02:19 PM   #23
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QuoteOriginally posted by ChristianRock Quote
I wouldn't worry too much about crop or no crop, and especially about people's opinions. Does it take great looking pictures? Then go out and shoot
bingo!

11-04-2014, 02:29 PM   #24
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QuoteOriginally posted by Pablom Quote
I still get great wall prints from my taped over sensor so I don't know what the fuss is about.
Sorry, I was meaning if he needed a very big print, like advertising.
11-04-2014, 02:31 PM   #25
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QuoteOriginally posted by AquaDome Quote
The people with the equivalence charts never show you the third, fourth, or fifth columns where their "full-frame" compares to several medium-formats that their "miniature 135 format" was cropped from.
...or 4x5 or 5x7 or 8x10

My understanding is the the whole "equivalence" thing was to help people who had a lot of experience with film during their transition to digital and were expecting a certain FOV for a given lens.

Don't worry too much about it, just be happy and shoot with what's in your hand.
11-04-2014, 02:59 PM   #26
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QuoteOriginally posted by Undot Quote
Maybe I misunderstand the process but isn't that like cropping afterwards? Only using a smaller portion of the film/sensor sensitive area?



*snip*
You got it.
Shooting FF and cropping in your favourite post processing software is exactly the same as using the same lens on APS-C.
11-04-2014, 03:13 PM   #27
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QuoteOriginally posted by LensBeginner Quote
You got it.
Shooting FF and cropping in your favourite post processing software is exactly the same as using the same lens on APS-C.
Except for the part where you get 24 MP in the crop area of your K-3 and 15 MP in the crop area of your D800. SO ya, it's exactly the same except when it isn't. And then you don't get exactly the same. You get at least 20% more resolution inside the crop area, with the APS_c camera. The only way to match up with FF, use a longer lens.

If you're thinking film.. when I need better resolution but wanted to shoot 35mm instead of 645, I used a 32 ISO extremely fine grained copy film. I used a smaller format, but with much finer grain, to create exactly the same effect as if I'd use the a 645 camera with much larger say Tri-X, maybe even better. You've always been able to get the same result out of a smaller format as you could with the next size up, as long as you had enough light, and finer grain. These days, it's smaller pixels instead of finer grain, and as before, as long as you have sufficient light, you can get pretty much the same result.

People who get drawn into this kind of thing, are generally people who don't have a very complete understanding of photography, and even less experience, and are looking for easy answers to try and make sense of it. IMHO, theories like equivalence are very misleading.

You don't know what you can accomplish with each format less you try it. Until then, you're trying to become a good basketball player, by reading a book about the physics of basketball.You an find out you want the ball falling towards the basket at a 60 degree angle, you can read aiming for the back of the rim works and aiming for the front of the rim doesn't. But put you on the foul line, and you still can't make a shot. At some point you have to stop thinking about equivalence, and go make some shots.

And the first thing you'll learn about equivalence when you do that, is that you really didn't need to learn it. If you start looking through different lenses on different formats, it becomes real obvious real quick in a way that's much more useful than any theory will ever be. Practical working knowledge, as opposed to book learning. After all, would you let a guy do the wiring in your house if he'd just read a book about it?

So why would you take advice about what lens you should use to be the equivalent of your Sigma 70 macro on FF...based on some table he read. Especially since you could just use your Sigma 70 macro on the FF camera, and not suffer at all.

Last edited by normhead; 11-04-2014 at 03:32 PM.
11-04-2014, 03:17 PM   #28
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QuoteOriginally posted by normhead Quote
Except for the part where you get 24 MP in the crop area of your K-3 and 15 MP in the crop area of your D800. SO ya, it's exactly the same except when it isn't. And then you don't get exactly the same. You get at least 20% more resolution inside the crop area, with the APS_c camera. The only way to match up with FF, use a longer lens.

If you're thinking film.. when I need better resolution but wanted to shoot 35mm instead of 645, I used a 32 ISO extremely fine grained copy film. I used a smaller format, but with much finer grain, to create exactly the same effect as if I'd use the a 645 camera with much larger say Tri-X, maybe even better. You've always been able to get the same result out of a smaller format as you could with the next size up, as long as you had enough light, and finer grain. These days, it's smaller pixels instead of finer grain, and as before, as long as you have sufficient light, you can get pretty much the same result.
Ok, should have said "all other things (i.e. pixel density etc.) being equal"...
11-04-2014, 03:34 PM   #29
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QuoteOriginally posted by LensBeginner Quote
Ok, should have said "all other things (i.e. pixel density etc.) being equal"...
You're getting there. But not everything can be equal. They can have equal MP or equal pixel density, they can't have both things equal, they are different formats.
11-04-2014, 03:45 PM   #30
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QuoteOriginally posted by normhead Quote
You're getting there. But not everything can be equal. They can have equal MP or equal pixel density, they can't have both things equal, they are different formats.
Who cares about different MP count?
Only thing that matters for this analogy (crop in post, crop in camera) is that there's the same number of pixels in the crop area, hence the same pixel density.
Comparing the whole sensor of both formats is an entirely different comparison, and people often mix up the two, with all the ensuing confusion.
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