Format sizes, MPs and printing large

[scooby70]

As an outsider looking in...

The discussions on equivalent images does interest me and I've been down that road myself but what also interests me is the possibility of enjoying the differences between the various formats. Looked at like that, it seems a shame to try to equalise things.

I was therefore pleased to read this...

So I decided to switch to my Sony Alpha 55 SLT. On that camera I could use the 24-70/2.8 ZA at 60 mm instead. The Alpha 55 is an APS-C camera using the "sweet spot" of the lens so I could shoot at f/4 without consideration for soft edges and jack up ISO a bit. Both images were similar, but I feel that the Alpha 55 images have some advantage.

[BJL]

... what also interests me is the possibility of enjoying the differences between the various formats.

That is a good perspective: think about what the strengths and weaknesses of various formats and equipment options, and the try to match gear to various interests and objectives.

But for those of us who live under constraints on he size, weight and cost of gear we can carry, there is an obvious resson for comparing performance on equal compositions: it makes sense to ask "do I need the bulkier, more expensive gear option for what I want to do, or can I get close enough to the same composition with a lighter, cheaper option?" Because if I can, then I also have the alternative of using the saved weight and money to have a more diverse kit (more lenses?; cameras in several formats?) allowing me to get a wider variety of good photos within the same constraints on bulk and cost.

[ErikKaffehr]

Hi,

Enclosed is an image where I feel that background branches need to be sharp all out to the corners. I was fortunate enough to reshoot it with a better lens a couple of days later.

There is a small story attached to this image. I shot it using an 10 MP Alpha 100 (APS-C) a couple of years ago that was pretty sharp, so I tried to make a 70x100 cm print from it. To my surprise it turned out good enough. Not good for pixel peeping at 40 cm but viewed at > 80 cm it is OK. I wanted to reshoot the subject with a higher resolution camera.


Attachements:

1) Full image with weak lens
2) Corner crop from 1)
3) Corner crop from image taken with sharp lens (an old Minolta 80-200/2.8 APO)
4) A more central crop (along center of long edge) on the weak lens (Sony SAL 70-300/4.5-5.6)

This composition requires around 150-160 mm. As i want background be dominated by the dark pine forrest. Moving just a couple of meters forward ruins the image and moving back puts you on the middle of the road and puts a couple of power lines into the image. Situations like this is one of the reasons I almost always use zooms.

Best regards
Erik

And if one has a primary interest in sharpness of the subject focused on, maybe a bit of corner softness is less important that optimum performance near the center: the OOF affects are likely to overwhelm a bit of corner softness most of the time (how often is something in the extreme corner in completely sharp focus?) At center it seems to be a close context between f/4 and f/5.6 for both lenses, with f/8 in third place!