NEW 50mmf1.2 MTF charts v 1.4

I Simonius wrote in post #2226470
thanks for the link and it sort of helps , only somewhere i also read that black lines = resolution + Blue lines = contrast.........???

Without taking the time to refresh my memory, I seem to remember that contrast was seen in how close the thick line is to the thin line. I just can't remember if closer together is more contrast or less

what I saw from MTF are

1. good contrast
2. bad resolution with aperture fully open, as bad as 50/1.4 at f/1.4.

my 2 cents,

it's not that worthy to buy if only judged from MTF.

But I would like to mention, in my experience, sometimes canon's offcial MTF has some problem. They couldn't tell you the whole story and sometime they mislead you.

How about just trying them out and seeing if you like it? I never place too much attention to charts. Nice clean test images are enough for me.

Longwatcher wrote in post #2226898
Okay Let me try
At least I gave it a try,

and I thank you for that - but the diferences look tiny.. would it make a noticable difference IRL?

One of the things that originally confused me was here
http://www.luminous-landscape.com …s/understanding​-mtf.shtml
where he makes the 400mm comparisions later in the essay and he suggests that the 5.6 FFL (fixed focal length) is better than the zoom, yet AFAICS the zoom MTF has higher thick and thinlines, e.g. the FFL has the thin blue line start (LHS) just above o.8 and go to (RHS) 0.8 whereas the zoom has the same line start at about 0.95 (much higher up) and go to (RHS) 0.8 at almost eactly the same point that the FFL startsout at

I tought this should mean that the zoom has higher resolving power at f8 in the centre and as good resolution at the edges as the FFL has at the centre - yet he maintains the FFL is better???

Don't get it :-C

foghorn wrote in post #2227722
How about just trying them out and seeing if you like it? I never place too much attention to charts. Nice clean test images are enough for me.

I would if someone had one to lend me but I don't have over £1200 lying round for trying out lenses to see if I like them

Unfortunately no one I know has even started posting pics yet from this lens either so the MTF s are all there is to go on at the moment

I Simonius wrote in post #2228561
and I thank you for that - but the diferences look tiny.. would it make a noticable difference IRL?

One of the things that originally confused me was here
http://www.luminous-landscape.com …s/understanding​-mtf.shtml
where he makes the 400mm comparisions later in the essay and he suggests that the 5.6 FFL (fixed focal length) is better than the zoom, yet AFAICS the zoom MTF has higher thick and thinlines, e.g. the FFL has the thin blue line start (LHS) just above o.8 and go to (RHS) 0.8 whereas the zoom has the same line start at about 0.95 (much higher up) and go to (RHS) 0.8 at almost eactly the same point that the FFL startsout at

I tought this should mean that the zoom has higher resolving power at f8 in the centre and as good resolution at the edges as the FFL has at the centre - yet he maintains the FFL is better???

Don't get it :-C

You do sometimes see this, don't forget the Canon MTF data is computer simulation not measurement.

One might assume the zooms "loose" more IQ due to higher complexity of construction but this does not always seem to be the case.

I had too much time on my hands at one point and did do a cross check between Canon MTF charts and Photodo MTF measurements and the zoom/prime departure from the two was similar at a given focal length.

It does seem the Canon MTF data is a good guide to lens IQ, but if the curves are very close then individual part to part variation probably makes the difference moot.

As for as the 1.2 and 1.4 50mm go the stopped down performance should be identical, wide open the 1.2 is a bit worse than the 1.4 which is to be expected for a faster lens.

The ratio of the S and M lines is said to partly indicate bokeh, the closer to gether the better. Wide open the 1.2 is worse inside a 15mm image height and better outside.

The MTF does not tell us anything about CA.

To me, these charts are useless information.

MegaTron wrote in post #2228668
To me, these charts are useless information.

to you,.. perhaps

Lester Wareham wrote in post #2228657
You do sometimes see this, don't forget the Canon MTF data is computer simulation not measurement.

One might assume the zooms "loose" more IQ due to higher complexity of construction but this does not always seem to be the case.

I had too much time on my hands at one point and did do a cross check between Canon MTF charts and Photodo MTF measurements and the zoom/prime departure from the two was similar at a given focal length.

It does seem the Canon MTF data is a good guide to lens IQ, but if the curves are very close then individual part to part variation probably makes the difference moot.

As for as the 1.2 and 1.4 50mm go the stopped down performance should be identical, wide open the 1.2 is a bit worse than the 1.4 which is to be expected for a faster lens.

The ratio of the S and M lines is said to partly indicate bokeh, the closer to gether the better. Wide open the 1.2 is worse inside a 15mm image height and better outside.

The MTF does not tell us anything about CA.

many thanks for that

Just had a look at your site - jeepers you know what you're talking about!

Thanks to everyone that posted = I think I have the hang of it now.. I thought I did before but the comments re the 400mm lenses confused me, they still do but as far as the 50mm lenses go I think I have got it

Cheers

adas wrote in post #2225096
It's not even a stop, it's only half of a stop.

It's not even half of a stop, it's only one third of a stop.

Lani Kai wrote in post #2231070
It's not even half of a stop, it's only one third of a stop.

I think that discussion has already appeared on here. It's all down to rounding. At these low f/ numbers, you really need a second decimal place. One-third, half, and two-third stops between f/1.0 and f/1.4 (actually f/1.41) would be 1.15, 1.22 and 1.29. The first two round to 1.2 and the third concatenates to 1.2, so you might say it could be any of these. In any case, the half stop would be the nearer. How much it matters is for the reader to decide!

Lani Kai wrote in post #2231070
It's not even half of a stop, it's only one third of a stop.

Aperture progression in 1/3 stop increments:
1.0 (2 to the 0 power)
1.122462048 (2 to the 1/6 power)
1.25992105 (2 to the 1/3 power)
1.414213562 (2 to the 1/2 power)

1/2 stop less than f/1 would be
1.189207115 (2 to the 1/4 power)

f/1.2 is more than 1/3 stop more, and less than 1/2 stop more than f/1.4.

But those numbers are rounded off anyway.

1/2 stop difference is the closest approximation.

Edit: Madweasel was quicker, but I used more digits!

I Simonius wrote in post #2228563
I would if someone had one to lend me but I don't have over £1200 lying round for trying out lenses to see if I like them

Unfortunately no one I know has even started posting pics yet from this lens either so the MTF s are all there is to go on at the moment

Then, why the fret and worry about the lens performance, if it isn't in your near future? Worry about it when you have the means.

I feel dizzy.

There's more to the lens than just aperture, thankfully. I'm assuming it'll have an 8-bladeed circular aperture like other new Ls, it'll have performance wide open optically, have the build quality of an L, work with E-TTL II and as a bonus on an L prime (at the low range)... Weathersealing.

A 1Ds with this lens would make a great setup in a lot of situations...