Boris, the colors are absolute. The 3D is because, well, there are three variables - the axis along the width of the image, the axis along the height of the image and the MTF.
charles.K: Lovely night shots!
rsolti13: Nice set!
Got a couple of rolls back today from two recent trips.
First a couple from Dortmund, Germany. Tried out a new film, I think I like it! Unfortunately the lab was not very careful when developing..
But it was pretty cheap
It's the MTF charts for the lenses shown across the image frame at different resolutions (10, 20 & 40 line pair/mm) and directions (sagittal and tangential).
If we look at the 28/35/50 comparison:
and we look at one of the charts:
The X & Y axis are simply the horizontal and vertical edges of the image. The Z (vertical) axis shows the MTF (i.e contrast). This is at a specific resolution, namely 40 lp/mm. For the M9, this corresponds to elements that have a radius of about 2 pixels. So it's the fine detail. The direction in this case is sagittal or radial, meaning that it's the resolution in the direction towards the image center. The other direction that is in a separate graph is tangential which you can visualize as circles around the center.
So what does this particular graph tell us?
Well, that the center sharpness for fine detail in the sagittal direction is very good (the red center) but that it drops off somewhere around mid frame (the dip in the surface/ green area) and gets better in the corners again. So if you have in your shot say a sandy beach, or anything with a fine texture, you can expect a drop in contrast in the direction towards the center of the image. This was from the 35 Lux. If we look at the same chart for the 28 Cron we see this:
We can see that the transition from the center to the edges is smooth. There is a drop in contrast for fine detail in the corners, but the transition is much more graceful without any wobbly parts in the middle.
If we look at them side by side just colorized by sharpness (MTF), 28 Cron on top:
That's how the sharpness for fine detail in the sagittal direction will vary in the shots that you take with the 28 Cron vs the 35 Lux. This tells you for instance that the Cron is definitely a better landscape lens - you don't want big swings in resolution in different places on the image when you are doing traditional landscape photography (i.e stopped down at infinity)
Infinity. The data is just from digitized Zeiss MTF charts. As for the colors, I thought you of all people would recognize Colormap Jet Not a Matlab user?
I took the MTF charts, converted them to numeric tables, did a spline interpolation and then just calculated the value of each position (i.e on a mesh) on the image frame .
Traditional views of MTF charts are very compact but as they are expressed only as function of the distance from the center of the frame it can be difficult to visualize the effect. This shows the MTF with color (and surface heights) on the actual 36x24 frame.
Regarding doing it on Canon glass - I can't. They don't give out real MTF charts, but simulated ones.
Luka, thanks for taking the time to 3d-ify the MTF charts. I guess my question is: what is the consequence for the differences in the sagittal and tangential graphs. I.e. the 28 Cron 40 cycles/mm is pretty smooth and gradual in the sagittal graph, but in the tangential graph it looks a bit more like the waviness of the 35 Lux.
I like the bench shot best from your last set - the layers of organic vs. linear shapes/lines is pleasing to me.
Joakim - there's a nice crispness to those images.
Malkovic - I hear good things about Portra films. I like these, and think they really suit the feel of Dortmund In this case, a definite Germany of the past feel with the colors. Also helps that the parking sign is in DMs.
One of the things I'm still envious about film is color or B&W negative films' more graceful transition to and handling of overexposed zones, such as bright light sources, or a sunset, etc.
KL, lovely sets! I like the variety of the first group and the first image of the BB players - has a nice feel in B&W.
Charles, I like the spontaneity of the street shot of the women with umbrellas!
Ryan, I don't mind the punchy colors - that's how I imagine life in Georgia must be Looks like your daughter doesn't mind dad constantly taking pictures. Hopefully that will last a while.
Joe, nice bike, though looks a bit heavy I meant to mention that I really liked the rendering of the previous images, of the church and the bike!
I feel I should post these before it's the middle of summer and completely out of season. Munich at the Englischer Garten (Munich's equivalent to Central Park), all with the CV75 f/1.8. The first was near wide open, might have been stopped down a touch. The last was wide open and the rest were somewhere in the middle, probably around 5.6 or 8. The three with the bright sky and branches caused some LOCA problems that I cleaned up quick and dirty in LR. I'd say it's as bad and possibly worse than the 85L in similar situations. But, considering it's a fast lens, not a big surprise.
Joe, Luka, Ryan, KL, Malkovic and Ron, thanks
Luka, really nice shots! Different style of compositions than usual
KL, very nice set. I love the expressions of shot #1, and the BW conversion is great
Luka, thanks... great stuff and information on the MTF charts!! It would explain why I have gravitated to using the 35 Lux more for environmental portraits, and the 28 Cron for seascapes/landscapes.
Malkovic, nice shots! I have never had any experience with Porta film, but it obviously handles highlights really well.
Joakim, nice shots! My fav is #2.
Ron, very nice set! Excellent examples of the CV 75. I really like #4 and 6. I do see the columns have crept into the shot!
Very nice set Ron - great light. #2 is my fav. Your obsession with columns is as bad as mine with ducks
rscheffler wrote:
Luka, thanks for taking the time to 3d-ify the MTF charts. I guess my question is: what is the consequence for the differences in the sagittal and tangential graphs. I.e. the 28 Cron 40 cycles/mm is pretty smooth and gradual in the sagittal graph, but in the tangential graph it looks a bit more like the waviness of the 35 Lux.
Now that is a good question, and I've got an idea how to illustrate it. Sagittal or radial is the sharpness in the direction towards the center of the image while the tangential is in the direction of circles around the image center (perpendicular to the sagittal direction).
Now for the illustration - we start with this image, shot around f/5.6 and more or less infinity:
First we look at the sagittal curves (40 lp/mm), and overlay them on to the image:
We're in luck - the ship is divided by a zone with high resolution (red) and a part with lower (green). If we compare the front and the back of the ship we get this at 100%:
The blue arrows are in the direction of the blur. That's how of a drop in sagittal MTF looks like.
If we instead look at the equivalent tangential overlay:
We can see that we start losing definition in the corners. Here's a corner crop:
the arrows are again (very roughly) in the direction of the blur. This is quite common - many lenses will produce a sort of swirly blur in the corners. That's blur in in the tangential direction.
hi all,
Just a quick request for recommendations of film/neg/slide scanners - have received an M2 on long-term loan, figured i should get a scanner to go along with it.
singletrack wrote:
hi all,
Just a quick request for recommendations of film/neg/slide scanners - have received an M2 on long-term loan, figured i should get a scanner to go along with it.
Tx!
kl
I can recommend the Epson V5000 or V7000 scanner with the Betterscan holders and ANR inserts.
Malkovic, interesting shots - a very retro feel to them.
Charles, nice capture - a good combination of moving and static subjects
Quarnevalen was today in Stockholm. It's a sort of parade with floats built by engineering students from the Royal Institute of Technology. It's held every third year - I was a participant way back in 1999. According to the newspapers almost 500,000 people showed up today to watch it.
As the parade passed right by my office I took up a strategic position in a window, but found the angle to be too restrictive after a while so I went down to ground level. I had the M9 and three lenses - 28/50/90 and it worked OK most of the time. I had some serious flaring problems with both the 50 & 28 (without lens hood) though and on the whole an AF camera with a tele lens would have perhaps been a better tool for the job.
