A simple test: Which is better A or B?

elf · Post by **elf** » Mon Feb 14, 2011 8:57 pm

Here are two single frame stacks with different lens at close to the same magnification.

Image A:

Image B:

Image A 100% crop:

Image B 100% crop:

A Large version: http://img.photobucket.com/albums/v649/etfrench/Ab.jpg
B Large version: http://img.photobucket.com/albums/v649/etfrench/bb.jpg

OzRay · Post by **OzRay** » Mon Feb 14, 2011 9:48 pm

Visually, I prefer the second one, because the lighting is better in my view, as it highlights the various parts a lot better. But I guess it depends on what you're looking for.

Cheers

Ray

morfa · Post by **morfa** » Tue Feb 15, 2011 12:08 am

I too prefer the second one and mostly for the same reason (lighting). If I had to pick a favorite purely based on detail rendition it would be the second one as well – from what I can see the first one appear a little softer.

realjax · Post by **realjax** » Tue Feb 15, 2011 1:24 am

Well, I like the first one better. Allthough the 100% crop may be softer, the light is better in my view, more detail is shown in areas where the second one seems a bit too bright. And who cares for the 100% crop. Besides us I mean

AndrewC · Post by **AndrewC** » Tue Feb 15, 2011 2:20 am

Prefer b)

- lighting is better
- composition is better (a has too much of the top lichen cropped off)

... but what are you wanting us to comment on ? Aesthetics or pixel peeping ?:)

seta666 · Post by **seta666** » Tue Feb 15, 2011 3:11 am

Same here, B looks crispier (pixel peeping wise)

lauriek · Post by **lauriek** » Tue Feb 15, 2011 6:50 am

I think the lighting has changed too much for us to judge the lenses. I prefer the second shot but I'm pretty sure that has a lot more to do with the lighting than the lens... Good try though, I know how tricky it can be to try to run these tests and only change one thing - it's almost impossible for me to change lens without changing lighting as things stand..

ChrisLilley · Post by **ChrisLilley** » Tue Feb 15, 2011 10:08 am

There is overall a bit more contrast in A, which means the shadows are darker and the detail is not seen in shadowy areas. This has the effect of making B look better in the close-up, but to me A looks better at the small size overall image as there is more of a sense of depth and shape. B looks 'flatter'.

Are these taken with different focal lengths? B looks almost compressed flat, as if taken with a longer lens.

B has slightly better definition of different greens (yellow greens from greener greens).

Some of this is likely to be lighting changes.

elf · Post by **elf** » Tue Feb 15, 2011 10:35 am

Thanks everyone for commenting. I didn't think the two lens would be anywhere close to each other in resolution before the test.

ChrisLilley wrote:There is overall a bit more contrast in A, which means the shadows are darker and the detail is not seen in shadowy areas. This has the effect of making B look better in the close-up, but to me A looks better at the small size overall image as there is more of a sense of depth and shape. B looks 'flatter'.

Are these taken with different focal lengths? B looks almost compressed flat, as if taken with a longer lens.

B has slightly better definition of different greens (yellow greens from greener greens).

Some of this is likely to be lighting changes.

Nice analysis. Lens A is the El Nikkor 50mm (@f5.6) and Lens B is Carl Zeiss 100mm 1:3.5 Tessar (@f8), an elderly large format lens. The lighting change was unintended. The light didn't move, but the subject was moved closer to the camera for the 50mm shot making the light more overhead.

I really expected the El Nikkor lens to be much better than the Carl Zeiss lens. The magnification is slightly less than 1:1 so the El Nikkor is slightly out of it's comfort zone. The color differences were also unexpected. I haven't noticed this with other lens.

Oskar O · Post by **Oskar O** » Mon Feb 21, 2011 3:47 pm

I agree that B is sharper and overall more pleasant due to the composition, but some small adjustments in the light could improve it further.

Around 1:1 I would expect that a dedicated lens would be easily superior the el Nikkor, but the old Tessar doing so well is somewhat surprising. However, Tessars can be very good in the central region. I'm thinking about a somewhat similar test myself, but need to kick myself to do it...

elf · Post by **elf** » Tue Feb 22, 2011 12:58 am

I might have to make a longer bellows and try it at 5X. I do have a 1 meter long aluminum extrusion that I could use. I'd also have to rewrite the software and change all the integers to doubles in order to count the stepper motor microsteps

There are probably quite a few other older longer focal length lens that would work well.

AndrewC · Post by **AndrewC** » Tue Feb 22, 2011 1:09 am

Remind me again, what exactly are you trying to achieve / investigate ?

elf · Post by **elf** » Tue Feb 22, 2011 1:18 am

When I started the test, I was really just interested in seeing how the elderly large format lens would compare to the El Nikkor for resolution. After everyone's comments though, I'd say that there are more important aspects to an image than the resolution. Composition, lighting, and color nuances seem to play a larger part in deciding which image is better.

AndrewC · Post by **AndrewC** » Tue Feb 22, 2011 1:23 am

So the elephant trunk bellows would just be to stress the lens at a higher optical mag ?

elf · Post by **elf** » Tue Feb 22, 2011 1:39 am

Yep, that's a good way to put it

Now that I think about it a bit more, it really wouldn't be very hard to do a looong extension. Take a set of cheap extension tubes, a cardboard mailing tube, and some gaffers tape ...