Why bother?


Horst

Link Posted 20/07/2014 - 10:07
Andrew, just imagine if you had a sensor half or a quarter the size of Your APS-C sensor, You could get away with a 50mm lens and fill the frame.
Regards, Horst

McGregNi

Link Posted 20/07/2014 - 10:12
The higher number of mp is only one aspect of the IQ equation. Your FF owing friend can content himself that he doesn't need that massive 500mm monster after all!
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andrewk

Link Posted 20/07/2014 - 10:15
I really don't know where you are going with this, Horst. We all know and agree (don't we?) that to have an image fill the frame in a FF camera, you need a lens 1.5x longer than you would with an APS-C camera. This longer lens costs more money. Simples!

Andrew
Flickr photostream

andrewk

Link Posted 20/07/2014 - 10:20
McGregNi wrote:
The higher number of mp is only one aspect of the IQ equation. Your FF owing friend can content himself that he doesn't need that massive 500mm monster after all!

My FF friend cannot afford the 500mm f/4 - but it is exactly what two lecturers at our club recently (both pro photographers - one on sports and the other on wildlife) bought so that they could get the best image possible quality. Apparently, most sports and wildlife photographers do that too - that's why you see all those dustbin lid size lenses at football matches.

Andrew
Flickr photostream

Horst

Link Posted 20/07/2014 - 10:20
Andrew wrote:

Quote:
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!!

Cropping has always been around, In Film and digital cameras. You get rid of the irrelevant or disturbing items. or you highlight the item you specifically want to see.

when I was young and did my own developing and printing, I always cropped when I saw a need to do it. That's just part of it.

With FF you can crop to your APS-C size without loosing definition.

Regards, Horst

andrewk

Link Posted 20/07/2014 - 10:27
Horst wrote:
With FF you can crop to your APS-C size without loosing definition.

I think you are missing the point here. Folks who invest in FF cameras do so because they want the best image quality. The only way to get that is to buy a lens long enough to do the job WITHOUT cropping.

Andrew
Flickr photostream

Horst

Link Posted 20/07/2014 - 10:31
Andrew wrote:
Quote:


I really don't know where you are going with this, Horst. We all know and agree (don't we?) that to have an image fill the frame in a FF camera, you need a lens 1.5x longer than you would with an APS-C camera. This longer lens costs more money. Simples!

Andrew, No you don't, maybe the way I am trying to explain it is not very good.
Maybe McGregNi can do a better job,having English as its first language

Regards, Horst
Last Edited by Horst on 20/07/2014 - 10:32

Blythman

Link Posted 20/07/2014 - 10:31
Horst wrote:
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

With the same size sensor, its like focusing on an animal (say a bird, 6 metres away) with a 300mm lens. and then from the same distance focus on the same bird with a 200mm lens. Assuming you want the eye sharp, and all other things being equal,which lens do you think would give you the most keepers?

Of course in your example where the animal fills the frame, then we wouldn't need longer lenses than we already have. However, most wildlife photographers in the real world always wish they had more focal length
Alan


PPG
Flickr
Last Edited by Blythman on 20/07/2014 - 10:33

tyronet2000

Link Posted 20/07/2014 - 10:37
At the end of the day who gives a monkeys. We know what we have and what it is capable of and if we didn't, well, who buys a car without a test drive
Regards
Stan

PPG

Horst

Link Posted 20/07/2014 - 10:37
Alan wrote:
Quote:

With the same size sensor, its like focusing on an animal (say a bird, 6 metres away) with a 300mm lens. and then from the same distance focus on the same bird with a 200mm lens. Assuming you want the eye sharp, and all other things being equal,which lens do you think would give you the most keepers?

The eye will be sharp, no matter what lens you use, if it is correctly focused.

However you will get a better definition with a 300mmlens, because the eye is spread over more pixels.
but this is only relevant if you use the same size sensor for both lenses.

Regards, Horst

andrewk

Link Posted 20/07/2014 - 10:42
tyronet2000 wrote:
At the end of the day who gives a monkeys.

I thought I did, but I'm starting to lose the will to live. Time for breakfast!

Andrew
Flickr photostream

Horst

Link Posted 20/07/2014 - 10:44
Well same here, I am going to watch a Midsummer Murder in five minutes on the tele.

Till later and a few murders on.

regards, Horst

Blythman

Link Posted 20/07/2014 - 11:03
Horst wrote:
Alan wrote:
Quote:

With the same size sensor, its like focusing on an animal (say a bird, 6 metres away) with a 300mm lens. and then from the same distance focus on the same bird with a 200mm lens. Assuming you want the eye sharp, and all other things being equal,which lens do you think would give you the most keepers?

The eye will be sharp, no matter what lens you use, if it is correctly focused.

However you will get a better definition with a 300mmlens, because the eye is spread over more pixels.
but this is only relevant if you use the same size sensor for both lenses.

Regards, Horst

But with which lens are you more likely to nail the focus. The lens where the focus point is taken up by the eye and maybe other parts of the head, or the lens where the focus point takes in the shoulder too?
Alan


PPG
Flickr

davidstorm

Link Posted 20/07/2014 - 11:04
I agree with everyone.

Regards
David
Flickr

Some cameras, some lenses, some bits 'n' bobs

McGregNi

Link Posted 20/07/2014 - 13:25
Thanks David I need that support! It seems to me that points being made by Alan (for example) are not really supporting the need for longer focal lengths on FF, but rather the need for more focussing aids such as a higher viewfinder magnification. If 300mm is long enough for the subject but on FF you can't see it clearly enough then then you're really looking for, perhaps , a viewfinder magnifying function (say 1.5x), or use the live view already available. Its not therefore necessary to go and buy a 500mm lens just to help you focus more easily.
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
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