Why bother?


Horst

Link Posted 20/07/2014 - 00:13
Andrewk wrote:

Quote:

However, if I have a 300mm f/4 on an APS-C camera and a friend, at the same location, has a (approx) 450mm f/4 on his FF camera, we will both be able to fill the frame with the same image. The big difference between us is that he will have paid over ten grand for his 500mm f/4, but I'll have paid less than a grand for my 300mm f/4. I think I can see some advantage here in using APS-C for sports and wildlife.

WhatMcGregNi said is spot on. If you have a 300mm lens on an APS-C camera, It still is a 300mm lens , except that you take only 1.5 times less angle and it seems like it is more of a tele lens.
The image you have is contained in the 16Mp or 23Mp your APS-C
camera can do

Now if you had a FF camera, It would see the same image but it has a 1.5 times greater angle and because it has to have about 43Mpixels, when to go to Lightroom or a similar program, you then crop it to the 16Mpl area and you have exactly the same image with the same quality as your APS-C camera. However you have the option to have if you just leave it as it is , to see more on your picture.
Facit: You need not a 450mm lens, You don't loose anything, but you need a lens that covers full frame.

The end effect is, your Rabbit or wild chicken will with the same lens have the same resolution on FF or APS-c.

Regards, Horst
Last Edited by Horst on 20/07/2014 - 00:14

Blythman

Link Posted 20/07/2014 - 00:18
Horst wrote:
[b] you then crop it to the 16Mpl area and you have exactly the same image with the same quality as your APS-C camera.

Not necessarily.

Assuming that the AF point is the same size on each sensor then, it can be more accurately set on APS-C. So you might have the eye in focus with the crop and out of focus with the FF as on FF it covers a larger area of the animal
Alan


PPG
Flickr
Last Edited by Blythman on 20/07/2014 - 00:19

andrewk

Link Posted 20/07/2014 - 00:41
Horst wrote:
Now if you had a FF camera, It would see the same image but it has a 1.5 times greater angle and because it has to have about 43Mpixels

One mate has a notPentax 5D MK1 which is 12.8 megapixels (and others have 5D MK2 or 6D - both around 20 mp) - so it doesn't work out quite like that. Practically, I can take the same photos from the same locations on my 16 mp (or 24 mp if I had a K3) APS-C using a lens at less than one tenth of the cost.

Andrew
Flickr photostream
Last Edited by andrewk on 20/07/2014 - 00:44

pschlute

Link Posted 20/07/2014 - 00:47
andrewk wrote:
Horst wrote:
Now if you had a FF camera, It would see the same image but it has a 1.5 times greater angle and because it has to have about 43Mpixels

One mate has a notPentax 5D MK1 which is 12.8 megapixels (and others have 5D MK2 or 6D - both around 20 mp) - so it doesn't work out quite like that. Practically, I can take the same photos from the same locations on my 16 mp APS-C using a lens at less than one tenth of the cost.

Andrew

I think his point is that you have to enlarge/magnify you image more than he does (with a FF sensor).

Is this relevant? Possibly, depending on your skills as a photographer. But you cannot debunk his science.
Peter



My Flickr page

K10D

Link Posted 20/07/2014 - 00:56
Ooh look, another APS-C vs FF thread.

Horst

Link Posted 20/07/2014 - 01:04
Blythman wrote:

Quote:
Assuming that the AF point is the same size on each sensor then, it can be more accurately set on APS-C. So you might have the eye in focus with the crop and out of focus with the FF as on FF it covers a larger area of the animal

Hello Alan.
Focus is only 2 dimensional, forget depth of field.

Say the animal stays at right angle to you, and half of it covers the APS-C size sensor, Then with FF it will of course cover, say 3/4 of it.

Even if you had a FF lens with not very good edge sharpness, when you crop it back to the APS-C size, (16Mp) it will be exactly the same.

If the animal looked at you, and you had the eye in focus, everything else would be out of focus anyway, except all the items which are at eye level at the time.
The exact Ficus is only at one depth position. Irrelevant if you use the lens at f 0.5 or at f64.

Regards, Horst
Last Edited by Horst on 20/07/2014 - 01:05

andrewk

Link Posted 20/07/2014 - 01:12
pschlute wrote:
I think his point is that you have to enlarge/magnify you image more than he does (with a FF sensor).

I may not have explained what I meant quite as well as I intended, so I will try again.

Let's suppose that I have a 24 mp APS-C camera and 300mm f/4 lens fitted. My mate has a notPentax 24 mp full frame camera. If we both want to take the identical subject, filling the frame in the same way, he will have to use a lens that is 1.5x longer if we stand at the same location. His lens will cost many times that of a 300mm f/4.

Andrew
Flickr photostream

Horst

Link Posted 20/07/2014 - 01:13
K10D wrote:

Quote:
Ooh look, another APS-C vs FF thread.

That's how it indirectly started. I was wondering why lenses which are for APS-C exclusively, should not be marked with the 1.5 times focal lenght of FF lenses.
So its not really another APS-C Vs FF tread

Regards, Horst
Last Edited by Horst on 20/07/2014 - 01:14

Horst

Link Posted 20/07/2014 - 01:24
Andrew wrote:

Quote:
Let's suppose that I have a 24 mp APS-C camera and 300mm f/4 lens fitted. My mate has a notPentax 24 mp full frame camera. If we both want to take the identical subject, filling the frame in the same way, he will have to use a lens that is 1.5x longer if we stand at the same location. His lens will cost many times that of a 300mm f/4.

Hi Andrew. You have to compare apple with apples. A future Pentax FF will not have only 24Mp but the amount of pixels will increase proportionally to the increase in sensor size from APS-C to FF.
Otherwise there is not much point of having FF.

If you increase the amount of pixels proportionally, your pixel size will stay the same.
You will get the same noise figure with APS_C as with FF.
However you'll get more image on to the sensor.

I can not see Pentax , if ever, releasing a FF with 24Mp only.

Regards, Horst
Last Edited by Horst on 20/07/2014 - 01:26

McGregNi

Link Posted 20/07/2014 - 08:39
I don't see it as being sensor related, rather its solely about lens focal length and the resulting perspective effects of different lengths ... These two factors are exactly the same on both formats. Andrew and his friend standing together shooting the same thing each with a 300mm lens will record the subject at exactly the same magnification and with the exact same effects of perspective ... The only thing his FF-using friend needs to do to make his image identical to Andrew's is to crop off a lot of the edges.

I don't really recognise the points made by Alan about focus points as relevant. We don't see the senor or the image projected onto it at all ... We see the scene through a viewfinder which is magnified to fill the amount of space the camera maker has allocated for it. It makes no difference how big the sensor is, we just see the full image circle because the viewfinder magnification is set to show us that, on both cameras (assuming a spec of 100%).
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
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Horst

Link Posted 20/07/2014 - 09:37
Looks like your out of bed already,

Here Its Sunday 6:30 pm
I agree with all you said, It is really quite simple if you look at it logically.

Regards, Horst

McGregNi

Link Posted 20/07/2014 - 09:47
I think the 'problem' arises from a human factor, not technological. We have a human need to 'fill the frame', that's been ingrained as a human best practice. In fact the only requirement is to select the right focal length to get the magnification needed .. This depends solely on how far away we are from the subject. This plus lens focal length is the same for both formats. What our FF photographer will not get is his human need for frame filling as much as the aps-c photographer. But he doesn't need a longer telephoto to fullfill that need, he just needs to crop his image.

Equally, if he can't see the subject clear enough or his focus points are too small, he doesn't need a longer lens, he needs more viewfinder magnification or to use live view and zoon in on the LCD.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 20/07/2014 - 09:50

andrewk

Link Posted 20/07/2014 - 09:51
McGregNi wrote:
Andrew and his friend standing together shooting the same thing each with a 300mm lens will record the subject at exactly the same magnification and with the exact same effects of perspective ... The only thing his FF-using friend needs to do to make his image identical to Andrew's is to crop off a lot of the edges.

Exactly so - but for him to fill the frame from the same location in camera, he needs a lens 1.5x longer which costs him megabucks, which is the point I was making.

Andrew
Flickr photostream
Last Edited by andrewk on 20/07/2014 - 10:01

Horst

Link Posted 20/07/2014 - 10:04
No Andrew it does,t. Your 16 Mp stay 16Mp even with a FF with the same lens if the FF's resolution's has been comparatively increased.


Regards, Horst

andrewk

Link Posted 20/07/2014 - 10:07
McGregNi wrote:
What our FF photographer will not get is his human need for frame filling as much as the aps-c photographer. But he doesn't need a longer telephoto to fullfill that need, he just needs to crop his image.

My bet is that our FF photographer's "human need" is to get the best possible quality from his investment. He will not get that by cropping!!

Andrew
Flickr photostream
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