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03-24-2018, 10:42 PM - 1 Like   #361
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QuoteOriginally posted by Rondec Quote
Of course. I finished my statement saying that I like crop sensors because they tend to be cheaper, smaller, and have very nice specs. I just get a little aggravated when someone mounts a 400mm lens on a micro four thirds camera and then claims they have an 800mm lens. No, they have a 400mm lens on a smaller sensor. That's fine, but not exactly the same as having, an 800mm lens and a D810.
It all depends on the F-stop. Having a 400mm F/5.6 lens on m43 is EXACTLY the same as having 800mm F/11.2 on FF. That's a silly comparison though, because nobody would produce or buy such a slow lens on FF - it will be faster, bigger, heavier, and more expensive.

---------- Post added 03-24-18 at 11:10 PM ----------

QuoteOriginally posted by Rondec Quote
I think wildlife photographers tend to gravitate towards bigger sensors over time. In good light micro four thirds is going to be fine, but unfortunately the light isn't always adequate to keep the iso low, particularly not when you are shooting with a long lens that is f5.6.

I also think reach is overstated by smaller sensor folks. A 400mm lens is a 400mm lens. The question is how much additional "reach" shooting it on a 20 megapixel micro four thirds sensor would give you over shooting it on a 24 megapixel APS-C sensor -- some, but it is not the additional 50 percent that some people seem to think it gives. The same is true for full frame versus APS-C. If you are shooting with a K-1, there is no additional reach gained by shooting with a 16 megapixel APS-C camera, while a 24 megapixel APS-C sensor does give some additional reach, once again it is no where near the 1.5 additional reach that the crop factor would indicate.
The difference in crop between m43 and APS-C is not that large - only 1.3x. So in reality it's only a 30% bump, not 50%. If you're willing to crop the 24mp APS-C down to 20mp then it's only a 19% increase in reach.

There's a true 50% increase from APS-C to FF, but again there's a difference in pixel density. If you're willing to crop 36mp down to 24mp it narrows down to a 22% increase in reach.

03-25-2018, 02:50 AM   #362
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QuoteOriginally posted by Mark Ransom Quote
It all depends on the F-stop. Having a 400mm F/5.6 lens on m43 is EXACTLY the same as having 800mm F/11.2 on FF. That's a silly comparison though, because nobody would produce or buy such a slow lens on FF - it will be faster, bigger, heavier, and more expensive.

---------- Post added 03-24-18 at 11:10 PM ----------



The difference in crop between m43 and APS-C is not that large - only 1.3x. So in reality it's only a 30% bump, not 50%. If you're willing to crop the 24mp APS-C down to 20mp then it's only a 19% increase in reach.

There's a true 50% increase from APS-C to FF, but again there's a difference in pixel density. If you're willing to crop 36mp down to 24mp it narrows down to a 22% increase in reach.
Umm. Sorry, I don't want to turn this into an equivalency 'discussion', --but-- isn't the apparent magnification more a question of pixel pitch on each format than the focal length of the lens (higher density pixels -> 'more magnification')? I mean otherwise you could just crop from the FF sensor to achieve the 'cropped omg magnification!' It is a 'cropped sensor' after all...

Ofc. to cover the larger image circle on larger formats the optics need to be larger, but focal length is focal length is focal length.
03-25-2018, 02:55 AM   #363
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QuoteOriginally posted by Chris Mak Quote
Both.I have decided that the KP will be my last Pentax body.
After that, I will go for a Canon 7DIII, which should come out end of year or beginning next year, together with a Canon 400mm f4 DOII, and the 1.4 and 2.0 extenders, which appear to work very well with this lens.
It feels like time....

Chris
You have echoed my post on another forum almost word for word although I will keep my K-1 and selection of lenses for full frame shooting.
Am also waiting for the 7DIII (currently use the MKI) and am looking for a mint 400mm f4 DO II
03-25-2018, 04:05 AM - 4 Likes   #364
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QuoteOriginally posted by fromunderthebridge Quote
Umm. Sorry, I don't want to turn this into an equivalency 'discussion', --but-- isn't the apparent magnification more a question of pixel pitch on each format than the focal length of the lens (higher density pixels -> 'more magnification')? I mean otherwise you could just crop from the FF sensor to achieve the 'cropped omg magnification!' It is a 'cropped sensor' after all...

Ofc. to cover the larger image circle on larger formats the optics need to be larger, but focal length is focal length is focal length.
If there's a 6 inch tall bird sitting in a bush 20 feet away, a photographer is most likely to wonder: what focal length do I need to have the bird fill 2/3rds of the frame height? For FF, the answer is 640mm. For APS-C, it's 427 mm. For M43, it's 320 mm.

Pixel pitch would matter if the photographer asks a slightly different question: what focal length do I need to have the bird be 3000 pixels high in the final image? In that case, the K-1 and the K-5 would need the same focal length (about 587 mm) and the K-3 would need only a 480 mm lens. (Note that a photographer might ask this question if they want the bird to be 15 inches tall in the final print when printed at 200 PPI.)

Although it's true that focal length is focal length is focal length, the goals of the composition (object size relative to frame size) or goals for printing (final print object size and preferred PPI print resolution) imply that different cameras require different focal lengths to accomplish the same image creation goals. Equivalency is just a short-hand way to say that one focal length on one camera format has the same photographic composition effects (angle-of-view, perspective, and distance compression) as some other focal length on some other camera format.

03-25-2018, 04:08 AM - 1 Like   #365
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QuoteOriginally posted by Mark Ransom Quote
It all depends on the F-stop. Having a 400mm F/5.6 lens on m43 is EXACTLY the same as having 800mm F/11.2 on FF. .
No it isn't as they will give different exposure. The numerical aperture do not refer to DOF.

Sorry for bringing up "equivalence". Equivalence doesn't exist.
03-25-2018, 04:16 AM   #366
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QuoteOriginally posted by photoptimist Quote
If there's a 6 inch tall bird sitting in a bush 20 feet away, a photographer is most likely to wonder: what focal length do I need to have the bird fill 2/3rds of the frame height? For FF, the answer is 640mm. For APS-C, it's 427 mm. For M43, it's 320 mm.

Pixel pitch would matter if the photographer asks a slightly different question: what focal length do I need to have the bird be 3000 pixels high in the final image? In that case, the K-1 and the K-5 would need the same focal length (about 587 mm) and the K-3 would need only a 480 mm lens. (Note that a photographer might ask this question if they want the bird to be 15 inches tall in the final print when printed at 200 PPI.)

Although it's true that focal length is focal length is focal length, the goals of the composition (object size relative to frame size) or goals for printing (final print object size and preferred PPI print resolution) imply that different cameras require different focal lengths to accomplish the same image creation goals. Equivalency is just a short-hand way to say that one focal length on one camera format has the same photographic composition effects (angle-of-view, perspective, and distance compression) as some other focal length on some other camera format.
Indeed. Quite right. Composition is quite the different matter. I was merely pointing out that focal length is focal length and distance to subject is distance to subject no matter how one cuts it.

I personally print my photos and I finalize the composition often in post (yeah.. embarassing isn't it?) so I'm actually interested in how many pixels of a bird I get and whether those are in focus so I guess I look at it from a different point of view.
03-25-2018, 04:21 AM - 1 Like   #367
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QuoteOriginally posted by photoptimist Quote
If there's a 6 inch tall bird sitting in a bush 20 feet away, a photographer is most likely to wonder: what focal length do I need to have the bird fill 2/3rds of the frame height? For FF, the answer is 640mm. For APS-C, it's 427 mm. For M43, it's 320 mm. Pixel pitch would matter if the photographer asks a slightly different question: what focal length do I need to have the bird be 3000 pixels high in the final image? In that case, the K-1 and the K-5 would need the same focal length (about 587 mm) and the K-3 would need only a 480 mm lens. (Note that a photographer might ask this question if they want the bird to be 15 inches tall in the final print when printed at 200 PPI.)
That's a great input for any wildlife photographer. Long big glass is one way of achieving good results, but it is expensive and heavy. There is another way, much cheaper: using wireless trigger. I used to use my K1 in crop mode with the DFA150-450 at 20 feet from subject, but now I am able to shoot in FF mode, I stay in a hide 7 feet away from the camera and I use my $10 IR remote to trigger AF and shutter. It saves myself buying a $10000 lens. I've seem some people even shoot wildlife with a wide angle lens using RF triggers to take the shots.
03-25-2018, 04:22 AM   #368
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QuoteOriginally posted by photoptimist Quote
If there's a 6 inch tall bird sitting in a bush 20 feet away, a photographer is most likely to wonder: what focal length do I need to have the bird fill 2/3rds of the frame height? For FF, the answer is 640mm. For APS-C, it's 427 mm. For M43, it's 320 mm.

Pixel pitch would matter if the photographer asks a slightly different question: what focal length do I need to have the bird be 3000 pixels high in the final image? In that case, the K-1 and the K-5 would need the same focal length (about 587 mm) and the K-3 would need only a 480 mm lens. (Note that a photographer might ask this question if they want the bird to be 15 inches tall in the final print when printed at 200 PPI.)

Although it's true that focal length is focal length is focal length, the goals of the composition (object size relative to frame size) or goals for printing (final print object size and preferred PPI print resolution) imply that different cameras require different focal lengths to accomplish the same image creation goals. Equivalency is just a short-hand way to say that one focal length on one camera format has the same photographic composition effects (angle-of-view, perspective, and distance compression) as some other focal length on some other camera format.
I think the thing is that if you had a 54 megapixel full frame with 8 frames per second in crop mode, other than cost and size, there would be minimal benefit to shooting with a K3 over such a camera. Crop sensors don't give additional magnification, except in as much as they have increased pixel density, but they do narrow the field of view for a given focal length. I just think that the way camera brands have marketed crop sensors in the past as "making your lenses longer" is somewhat duplicitous.

03-25-2018, 05:01 AM   #369
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QuoteOriginally posted by fromunderthebridge Quote
Indeed. Quite right. Composition is quite the different matter. I was merely pointing out that focal length is focal length and distance to subject is distance to subject no matter how one cuts it.

I personally print my photos and I finalize the composition often in post (yeah.. embarassing isn't it?) so I'm actually interested in how many pixels of a bird I get and whether those are in focus so I guess I look at it from a different point of view.
There's nothing wrong with post processing the composition. In fact more people should be selectively cropping their images in post to create a better final composition. Just as people use the RAW format to provide flexibility in post processing, using a slightly shorter focal length provides flexibility in cropping in post.

My key point was in the physical ratios of distances in front of the lens versus behind the lens. The ratio of subject distance to subject height is the same as the ratio of focal length to the height of the image of the subject on the sensor. That implies that a smaller sensor means that either a smaller subject "fills the frame" or that I can use a shorter focal length to get the same relative size of subject in the frame.
03-25-2018, 05:07 AM   #370
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QuoteOriginally posted by Rondec Quote
I think the thing is that if you had a 54 megapixel full frame with 8 frames per second in crop mode, other than cost and size, there would be minimal benefit to shooting with a K3 over such a camera.
Perhaps. The APS-C sensor camera would, as you say, be smaller, lighter and cheaper. Plus, an APS-C DSLR at the same level of development as that 54 MP whizz-bang full-frame model would likely be faster still (which may or may not be valuable). But most significant, I think, is that the APS-C DSLR's optical viewfinder shows the actual field of view you're capturing and nothing more. With the full-frame camera in crop mode, you're still looking at the full-frame field of view, but much of that is wasted because you're only interested in the central area. Of course, using Live View negates that, but it's not practical in every situation...

Last edited by BigMackCam; 03-25-2018 at 05:28 AM.
03-25-2018, 05:19 AM   #371
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QuoteOriginally posted by Rondec Quote
I think the thing is that if you had a 54 megapixel full frame with 8 frames per second in crop mode, other than cost and size, there would be minimal benefit to shooting with a K3 over such a camera. Crop sensors don't give additional magnification, except in as much as they have increased pixel density, but they do narrow the field of view for a given focal length. I just think that the way camera brands have marketed crop sensors in the past as "making your lenses longer" is somewhat duplicitous.
Then you are comparing a crop camera to a crop camera. One very expensive and heavy. You can turn this on its head and say there's no point buying an FF camera if you are going to crop anyway.
Strictly speaking it is true that you don't get more magnification with a cropped sensor. However, the magnification we are interested in as photographers is the subject size compared to the format we are using. In that sense smaller format gives larger magnification and "making your lenses longer" is perfectly true.
03-25-2018, 05:45 AM   #372
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QuoteOriginally posted by biz-engineer Quote
That's a great input for any wildlife photographer. Long big glass is one way of achieving good results, but it is expensive and heavy. There is another way, much cheaper: using wireless trigger. I used to use my K1 in crop mode with the DFA150-450 at 20 feet from subject, but now I am able to shoot in FF mode, I stay in a hide 7 feet away from the camera and I use my $10 IR remote to trigger AF and shutter. It saves myself buying a $10000 lens. I've seem some people even shoot wildlife with a wide angle lens using RF triggers to take the shots.
Quite true! I'm always in awe of the dedicated nature photographers that have the time to figure out or control where the animal will be.

But for us hikers and tourists who don't have the time or the equipment to set up a blind and wait, the only alternative is to create "reach" using either a longer lens, smaller sensor, or a more megapixels with cropping.
03-25-2018, 05:50 AM   #373
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The K-1 is not that much bigger than a K3 and the K-1 shoots 6.5 fps in crop mode versus the K3's 8 fps. Obviously it would be foolish to buy a full frame camera only to shoot in crop mode, but if you know that you are not going to be using the borders of your image anyway, then it works.

I'm sorry, but I still don't buy the lens longer argument and in particular, as pixels get more dense, it becomes harder and harder to get pixel sharp images.

But I apologize as well for this rabbit trail. This has nothing to do with the K3 III which hopefully will be announced by the end of the year and feature some higher level features than we have seen here to fore in a Pentax camera.
03-25-2018, 06:58 AM   #374
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QuoteOriginally posted by Rondec Quote
I think the thing is that if you had a 54 megapixel full frame with 8 frames per second in crop mode, other than cost and size, there would be minimal benefit to shooting with a K3 over such a camera.
Heheh - funny! "Except for these two HUGE differences, there wouldn't be any difference!"

Which is to say that even if there existed a 52MP, 8fps shooting, $5k+, K-WOW camera, I'd still be hoping for a K-3III in 2018!

QuoteQuote:
Crop sensors don't give additional magnification, except in as much as they have increased pixel density, but they do narrow the field of view for a given focal length. I just think that the way camera brands have marketed crop sensors in the past as "making your lenses longer" is somewhat duplicitous.
Yes, I do agree with that, and I've had that very "conversation" with macro shooters claiming to be shooting "2:1 magnification" when they're actually using a (standard, Olympus) 1:1 macro lens on their m4/3 bodies. Sometimes people will do anything to make themselves or their photos (or their lenses, if they are lens manufacturers) seem more impressive. At least in macro photography, the definition of magnification is pretty clear - even Olympus doesn't claim their 60mm macro as a "2:1" lens - so the precision of the definition gives me something solid to beat them over the head with rely on.
03-25-2018, 07:12 AM - 1 Like   #375
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QuoteOriginally posted by Doundounba Quote

Yes, I do agree with that, and I've had that very "conversation" with macro shooters claiming to be shooting "2:1 magnification" when they're actually using a (standard, Olympus) 1:1 macro lens on their m4/3 bodies. Sometimes people will do anything to make themselves or their photos (or their lenses, if they are lens manufacturers) seem more impressive. At least in macro photography, the definition of magnification is pretty clear - even Olympus doesn't claim their 60mm macro as a "2:1" lens - so the precision of the definition gives me something solid to beat them over the head with rely on.
But again photographers are not interested in exact subject magnification, but how much the subject fill the frame. To get an image like 1:1 maginification on 4/3, you'll need a 2:1 lens on FF. Or for the same frame filling properties you can use longer working distance on the smaller format; very useful for macro.
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