[ogl]

Can everybody please refrain from mentioning DoF when it comes to FF? It becomes incredibly boring.
Cannikin, please don't use this thread to do your resarch regarding DoF. Thank You.
I recommend reading the article on equivalent lenses on Luminous Landscape before replying, too.

Thank you, Falk

[paperbag846]

I want the 645D simply because I want to take portraits with only one mustache hair in focus .

In all seriousness though, the K-5 has made me seriously question the usefulness of FF for my purposes. The only thing I want is an increase in ASP-C dynamic range. I'm not sure if it is possible, but if it is, I will never buy a FF camera, even when I am "rich" (-er than a student) .

[cbaytan]

Can everybody please refrain from mentioning DoF when it comes to FF? It becomes incredibly boring.

I just can't believe how you can say people, refrain yourselves talking about DOF, when DoF is a great deal when comparing FF and smaller sensors. If you are bored (naturally) don't read it, if you you want to make contribution just do it. I guess what you have failed to see is some of the photographers huge DOF misconceptions between FF and smaller sensors are corrected here.

We all appreciate your technical skills and articles, I personally thank you, but it is normal that you get bored in some threads. If this is the case just refrain yourself reading those threads. This is a free forum and we can talk about anything we want. Ok Falk?

Or am I taking your post too seriously?

[telfish]

Hmm according to my simple DOF calculator on the Ipad which allows you to compare cameras side by side.

The K7 with a 50mm 1.4 lens set at 1.4 shows a DOF focused at 10 feet of .68 ft from 9'67 to 10'35
COC 0.020

A D700 same setup shows 1.02 feet DOF from 9.52 to 10.54 COC 0.030

To equal them up I have to increase the FF lens to a 61mm or increase the fstop on the APS to 2.2

Which is the exact opposite of common wisdom is it not? So something is wrong here somewhere, either in the app or in common wisdom.

Just for information I draw no conclusions. I can plug in any camera any f stop and any focus point if anyone wishes to know another setup.

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Last edited by telfish; 10-24-2010 at 10:59 AM.

[falconeye]

it is normal that you get bored in some threads. If this is the case just refrain yourself reading those threads. This is a free forum and we can talk about anything we want. Ok Falk?

Or am I taking your post too seriously?

So, I decided to talk about me getting bored. Which wasn't serious, of course

The problem is that it isn't possible to ignore a post w/o reading it. And I ignored the DoF topic until I couldn't stand it any longer...

I'm not against mentioning DoF in a FF thread. I'm against repeating the ever same misconception and wrong information about DoF. And then even seeing people fight the ever same fights. There's nothing to fight about. DoF was understood 100% 100 years ago! So, 90% of postings mentioning DoF belong into the "please, teach me DoF" threads, not FF.

FF is too important to see all threads mutate into DoF lessons. FF can sink Pentax if Pentax cannot cope with the subject. And that's not because Pentax doesn't understand DoF

[RBellavance]

Which is the exact opposite of common wisdom is it not? So something is wrong here somewhere, either in the app or in common wisdom.

The "something wrong" is that in practice, people don't use the same focal lenght from the same distance on 24x36 and APS-C formats.

[telfish]

The "something wrong" is that in practice, people don't use the same focal lenght from the same distance on 24x36 and APS-C formats.

Ok so to get the same .68 DOF I have to move the focus point in from 10 feet to 8 feet with the FF at 50 mm 1.4 does that seem right?

[Tord]

I don't need a FF camera. I'd like to have such option though.

Fully agree, but no hurry! If it will cost something like the 645D I am not interested, but if it costs just a little more than the K-5 costs now, bring it on!

[cbaytan]

Fully agree, but no hurry! If it will cost something like the 645D I am not interested, but if it costs just a little more than the K-5 costs now, bring it on!

Now we are talkin!

[Cannikin]

Cannikin, please don't use this thread to do your resarch regarding DoF. Thank You.

As a starting point, please note that some image properties are defined at an image level rather than a pixel level. In your example, you're right, the lens is rendering the same pixels but not the same images as an FF image simply has more of them. DoF is defined at an image level and therefore, your statement can be proven to be wrong. However, I won't do it in this thread...

I recommend reading the article on equivalent lenses on Luminous Landscape before replying, too.

I am not doing "research", these are simple facts of physics to anyone who knows anything about optics (a scientific field outside of cameras). An image has nothing to do with "pixels". Pixels are a purely digital concept. An image is an optical concept, just like glasses, magnifying glasses or mirrors produce images. The thing you see in the viewfinder is an optical image, but there are obviously no "pixels" involved there. The image created by the lens is simply light rays bent in such a way that they converge at the rear focal point and subsequently diverge at the plane of the capture medium. If you stick a piece of paper in place of the back of the camera, there are no such pixels to be found, but the exact same image is rendered on that piece of paper.

To produce the same field of view in your picture on FF, indeed the DOF will be different from the APS-C camera, whether from moving in closer or with a longer focal length. I mentioned this from the very start. This is a simple practical consequence of FF. I am not and have not been arguing against this.

My statement is very simple: if you take a picture with a FF camera, and crop that picture to match the field of view of APS-C, the crop will look exactly the same as the APS-C camera taken with the same lens from the same spot, DOF and all. I am seeing people act as if the FF sensor somehow changes the optical properties of the image, when this is not true.

Anyway, I am fine with dropping the topic. I just wanted to set the record straight after seeing people claim that FF's DOF advantage (a real thing from a practical sense) is due to "physics". It is a practical consequence of shooting technique involved with FF, not physics.

[falconeye]

My statement is very simple: if you take a picture with a FF camera, and crop that picture to match the field of view of APS-C, ...

Anyway, I am fine with dropping the topic. I just wanted to set the record straight

Want the last word?

Cannikin, the topic is settled in this forum. It's new members like you who bring it up again and again. Please, show the respect this community deserves and first do the research you have been kindly requested for.

You may start your research by understanding why cropping an image lowers its depth of field. E.g., try to understand what the Circle of Confusion is and how cropping changes it. And by pixel, I meant a relatively small and fixed sized region in the focal plane, like a 5x5 micron^2 region. I tried to make it simple for you to understand what I wanted to say, but obviously, you didn't care trying to understand.

And because this isn't a DoF lesson thread, no more from me in this thread about DoF.

[sifun]

what's the dynamic range like on the k5?

[Freak]

Extremely shallow DOF is another reason for FF, something APS-C can't offer to the same magnitude.

Higher resolution, bigger viewfinder, proper focal lengths, better crop ability, shallow DOF are just some of the advantages.

Why people try and compare APS-C compared to FX is a surprise to me, i would always own an APS-C, But i want to move up to fullframe, a 5DMKII is looking like it's on the cards for me at some stage, hopefully some of Pentax lenses could join it.


Now that we have the K-5, we no longer need Medium Format 645d either right?

[Laurentiu Cristofor]

My statement is very simple: if you take a picture with a FF camera, and crop that picture to match the field of view of APS-C, the crop will look exactly the same as the APS-C camera taken with the same lens from the same spot, DOF and all. I am seeing people act as if the FF sensor somehow changes the optical properties of the image, when this is not true.

You're correct, but this isn't really relevant. You're not using a FF camera to crop, so the results are different. Or, in other words, on APS, you have to get farther from the subject to get the same framing and that leads to more DOF. Whether that matters in any significant way is a different point that was carefully avoided.

Your statement and ogl's statement were both correct, except they don't contradict each other, but both of you failed to see that - it's funny how people reject even the truth if it just looks like a counterargument to what they believe is true.

Can everybody please refrain from mentioning DoF when it comes to FF? It becomes incredibly boring.

Good luck with that! Unfortunately, this is what most people inevitably dig up as an argument for FF.

Bottom line is: I'd like to see how many people can differentiate between images taken with FF cameras and images taken with APS cameras just from looking at them. If that can't be done, all these arguments are purely theoretical. Either the FF advantage allows doing something that obviously couldn't be done with an APS camera, or it is just an optimization that will be irrelevant in a generation or two, like faster AF.

[rparmar]

I see as little hope in people refraining from mentioning DOF in a FF thread as there is people refraining from mentioning FF in a forum dedicated to a camera manufacturer who has no current FF products.

It's all equally batty and equally boring.

On the K-5 score, it looks real nice and all, like every new camera does. Once they figure out how to put a FF viewfinder in it, with calibrated magnification so a normal lens has the correct eye feel... well then we'll be onto something.