Yeah Baby! I Like It RAW!

How thought provoking! Such language! Raw? Really? Ooooh, yeah baby! I LOVE it Raw! And no, not my steak. I want my photos RAW! Well, NEF works just as well, too. RAW provides me with the opportunity to be the Mistress of Manipulation…the Pharisees of PhotoShop! Either way, I get to decide! Woo hoo!

Ok, so I’ll explain all the hoopla. Jpg format is like eating in the camera’s chow hall. What ever the camera’s serving that day, is what I’m having. RAW (NEF) is like going hunting, killing it, skinning it and cooking it however I want it! Yeehaw! ‘Seasoned’ (post-processed) just right I can have one helluva meal! I’m saying goodbye to my Mickey Ds jpg and hello to my own personal gourmet RAW.

This is really a big step. I’ll be converting final products to jpg after processing. Yes, it’s time to learn some new software. I’ve got quite a few options including my in-camera processing (thanks, Nikon). Just for good measure, I purchased another memory card. 8Gigs. RAW files are pretty big. The saving grace is that instead of having to dump my pictures on my laptop, now, all I have to do is switch cards. An heir and a spare.

Tony, if you’re reading this, it’s time for photoChop lessons. Yes, I meant, PhotoCHOP! LOL!

MTF Anyone?

Ok, so MTF is not an acronym for ‘Meet The Family’, ‘Mothers Thank Fathers’ or ‘Marry The Fucker’. Nope. None of those. It’s short for Modulation Transfer Function. Defining each word individually doesn’t even come close to the definition of the three words combined.

When I first took a look at a MTF chart, my left brown went up and I was completely clueless. Everywhere I looked, photographers were citing MTF charts as a way of grading lens capabilities. Ok, the idea made sense until I actually looked at one. The chart looked like a square with squiggly lines. There was an obvious X and Y axis points and 4 lines, two solid and two segmented.

As I read the ‘oohs’ and ‘aahs’ of posters, I thought, “What are they looking at? I don’t get it.”

Ok, so I asked Kayne (yet another question) to make sense of it for me. Here’s what he wrote:

OK…. so…

What are MTF Charts… and how the heck do you read them?

First of all… MTF is an abbreviation for Modulation Transfer Function.

Light is… of course… altered or modified as it passes through a series of elements in a lens. An MTF Chart is a visual representation of this modification or altering of light as it passes through a lens.

A lenses quality is typically judged by its ability to sharply resolve fine details or its resolving power. This resolving power is dependent on a lenses abilty to accurately transmit contrast.

For example. Lets say we take a strip of white paper 1mm wide. And on that strip of paper we draw 50 black lines. The white spaces in between the black lines now become white lines. So in essence we now have 50 white lines and 50 black lines for a sum of 100 lines. Each of these lines is only .01mm thick.

Following me so far?

Good

Now… is a certain lens going to be able to accurately capture these lines as seperate black and white lines? Or is the lens going to turn them into a fuzzy mess?

A lenses ability to accurately resolve the seperate black and white lines depends on its ability to transmit the contrast between the lines through its elements. The less the modulation(modification/alteration) of the contrast between the black and white lines will result in a sharper image. More modulation of the contrast between the black and white lines will… of course… result in a more fuzzy looking image.

Simply… the less modulation the better the resulting image is going to be.

Now… lets take a look at an MTF Chart…

For this we will use the MTF Chart for Dee’s new 50mm f/1.8 AF-D lens

The Y-axis or vertical axis of the chart goes from 0 to 1. These numbers represent a percentage from 0% to 100%. So a 0.7 value on the Y-axis means the lens can transfer 70% of the contrast in a scene through it.

The X-axis or horizontal axis is measured in millimeters and represents distance from the center of the frame/sensor. With 35mm film… the maximum distance from the center of the frame is about 21mm.

So knowing this you can now look at the chart and see that the lens is better/sharper in its center as the modulation is less(higher percentage value).

But what do those four lines on the graph represent?

Good question!

Remember our little strip of paper only 1mm wide for this next part…

The top two red lines represent a test done with 10 lines per millimeter. This is a test of a lenses abilty to accurately reproduce contrast. The solid red line being Sagittal lines result and the dotted red line being the Merdional lines result.

The bottom two lines represent a test done with 30 lines per millimeter. This is a test of a lenses resolving power or resolution. The solid blue line being the Sagittal lines result and the dotted blue line being the Meridional lines result.

Sagittal and Meridional… there are those two words again…

This next image will show you what is meant by Sagittal and Meridional lines in a frame and how those results are measured…

So from that image we can see that Sagittal lines run parallel to a diagonal line that splits the frame from corner to corner. Meridional lines are at a 90 degree angle to the Sagittal lines.

Still with me?

I hope so because we’re almost done!

So we’ve got four lines…

One line representing Sagittal contrast.
One line representing Meridional contrast.
One line representing Sagittal resolution.
One line representing Meridional resolution.

With this new understanding take a look at the MTF Chart again.

Now remember…

The higher up the chart the solid and dotted red lines are… the better the contrast reproduction of the lens will be.

The higher up the chart the solid and dotted blue lines are… the better the resolution/resolving power and overall sharpness of the lens will be.

And finally an interesting note about these lines…

The closer together the lines are across the entire range of the chart… the better the bokeh of a lens will be.

Cool huh?

__________________
Kayne

And then he wrote:

I posted this explanation of MTF Charts over at Nikon-Digital.ca. Was asked by a member there how they could be used to compare possible results from another lens. I replied with this…

How can you use these to compare them to other lenses…

Lets do that for a moment… please keep in mind that these MTF Charts are a representation of a test done with the aperture at f/1.4.

We’ll compare the AF 50mm f/1.4 D to the new AF-S 50mm f/1.4 G

The two MTF Charts… the old AF-D is on the left and the new AF-S G is on the right…

Right off the top with a quick glance one can see that the new AF-S f/1.4 is generally better in both contrast(the red solid and dotted lines) and resolution(the blue solid and dotted lines)than the old version of the lens… especially in the center of the frame/sensor(value 0 along the X-axis).

Note: The center of the frame/sensor will coincide with the center of the lens. As you move to the right along the X-axis you move out from the center of the frame and out towards the outer edge of the lens.

5mm out from the center of the frame/sensor the new 50mm is still about 10% better in transmitting both Sagittal and Meridional contrast. When it comes to resolution though… the old 50mm starts to catch up at this point. Meridional resolution is pretty much the same but Sagittal resolution in the old one is about 5% behind.

10mm out from the center of the frame/sensor the new 50mm is still better at transferring both Sagittal and Meridional contrast through it. At this point though the old 50mm beats the new by about 5% at transferring Meridional resolution but lags behind the new lens by about 7-8% when transferring Sagittal resolution.

15mm out from the center of the frame the new 50mm is better at transferring Meridional contrast by over 10%. Its also better with Sagittal contrast but only by a few percent. With Meridional resolution the new lens is almost a full 20% better than the old lens. But only better by a few percent with Sagittal resolution.

20mm out from the center of the frame the new 50mm is about 15% better at transferring Meridional contrast. But is actually a few percent worse with Sagittal contrast. The new 50mm is a few percent better with both Meridional and Sagittal resolution than the old lens.

Also with looking at the overall plotting of the lines… one can probably deduce that the new 50mm has a more pleasing bokeh… but it would be pretty close between the two.

Overall when comparing the charts one can see that the new 50mm is sharper and has better contrast than the old 50mm when shot wide open.

__________________
Kayne

If I didn’t get it after this incredible explanation, I am never going to get it. And pretty pictures to boot!

Eyes wide open, yet seemingly closed?

As a newbie, I’m constantly bashing the mathematical and logistical systems of photography. Why? Because I want things laid out simply and with the greatest of ease. The expectation of newbies like myself, is to pay good money for a camera and instantly become Ansel Adams or even a Fred Miranda. Why not? Would it not be great to write a check and become an instant celebrity? Would it not be great to wake up one morning with the years of mastery of the greats simply by making a purchase? Wishful thinking, of course…but it ain’t gonna happen for me. So, in the mean time, I reckon I’ll get my fancy photography learnin’ the ole fashioned way….. I’ll try…then I’ll try some more.

Let’s talk about Aperture. This bigger the F-stop, the smaller the aperture (opening). It can get confusing. I want to believe the opposite. Why? Because it would make it easier, but unfortunately, it would be ALL WRONG!

So here’s what ‘Sensei’ Kayne says from ProDslr.com:

“It would definitely be more intuitive for beginners, yes. But just like almost everything when it comes to photography, there is math involved. Having it done that way would be totally opposite when it comes to the mathematical equation that determines the f/ stop or aperture size.

The equation… in case you’re wondering is…

f/# = N = f/D

Where f equals the focal length of the lens and D equals the diameter of the entrance pupil of the aperture.

So basically… if the focal length is say 8 times the diameter of the entrance pupil… that is f/8.

Using your new 50mm lens as an example and plugging those numbers into the equation… at f/8 the diameter of the entrance pupil at the time of exposure is only 6.25mm.

Not very big… is it?

And that wouldn’t let a lot of light into the lens.

Where as at f/1.8 the diamater at the entrance pupil is 27.8mm(rounded up).

Which… of course… will let a lot more light into the lens at the time of exposure.

And considering the aperture size is yet another mathematical equation pertaining to an actual measured amount of how much light is let into a lens(Aperture Area)… Gary summed it up pretty good…

A 1 to 1 ratio is… theoretically… all the light that can be let into a lens.

And that… of course… would be f/1 __________________
Kayne

Ok, so you haven’t heard of Kayne, but who cares. He know’s what he’s talking about and for the most part, that’s all that matters.

New Lens – 50mm f/1.8D

What the hell have I done? I just HAD to purchase a new lens. HAD to do it. Why? Well, I was under the impression that I needed a prime lens. Not sure why I needed a prime, I can barely use, understand or even spell the names of the lenses that I have. SO why did I do it? Well, because………ummm, see what happened was………. Alright it was a bargain. It was cheaper than the my bikini and boots ensemble. Ok, well maybe that was too much information, but you get my drift, right?

Lesson for today: Don’t purchase things you don’t understand….even when it’s cheap.

Here’s the (modest) gear list: Nikon D90, Sigma 10-20mm f/4-5.6 EX DC HSM, 18-105mm VR, 55-200mm VR, Nikon 50mm f/1.8D, SB600, Gorillapod, Nikon ML-L3 Remote

If I purchase anything else without knowing how it works, feel free to slap me.

How Many Elements in How Many Different Groups?

On my favorite newbie friendly photography website, ProDSLR there is a thread where a poster mentions that a particular lens has “15 elements in 11 groups.” My first thought when I read the post was, “What did you say about my mother?” Surely the post represented some sort of photography-related hieroglyph and that I should make my way to the nearest camera shop to purchase my very own Rosetta Stone. I didn’t have to do that at all. The original poster, Kayne, was kind enough to clarify what he wrote with such detail that there could be no misunderstanding. He said that he didn’t mind if I reposted what he wrote in my blog. Here it goes:

15 elements in 11 groups is the lens construction Dee. Take a look at this illustration…

If you count the pieces of glass in the lens you will see there are 15 of them. They are referred to as elements. The 11 groups are the number of those elements that move for focusing. A group is a piece of glass that has a bit of space in between it and the next closes piece of glass to it. Or two pieces of glass that are fit together that have space between them and next single piece of glass or two pieces of glass that are fit together. Now… in the illustration you can see 4 pairings of elements… these being 2 pieces of glass that are very close together in the illustration. They are the ones that look like they have just a sliver of space in between them. Inside a lens these pieces of glass touch each other. Those 4 pairings move in conjunction with one another. These pairings are considered 4 groups. The rest of the individual pieces of glass make up the other 7 groups. Altogether they make up 11 groups.

Something that might make this a bit clearer for you… take a look at this illustration of the 14-24mm f/2.8 AF-S lens…

This lens has 14 elements in 11 groups.

Now take a look at this next picture… its the 14-24 cut in half. You can clearly see the 3 pairings(groups) of elements that are touching each other. There are two right at the lens mount. Then three individual pieces of glass. Then another pairing.


Kayne’s pretty smart, huh? If after reading this explanation, you don’t ‘get it’, consider another hobby. If by chance the explanation provoked more questions, I’ll venture to say you’re on the right track.

Naturally, I had more questions after Kayne’s explanation, so I asked him the following:

1. Is there a standard? Meaning, Is an excellent lens one that has lots of pairings and lots of elements?

2. What’s minimum number of elements or pairings that you look for in a lens?

3. What is the function of the pairings (the ones close together)?

I know you don’t build the things, but if you happen to know, please tell me .

In looking at the close pairings, I can’t help but wonder why they simply don’t use ONE larger piece of glass instead of two.

His responses were as follows:

1. There is no standard to the amount of elements and groups that comprise what would be considered an excellent lens or any lens for that matter. A lens is constructed in such a way as to minimize or eliminate as many optical aberrations as possible. Whether the lens is a prime, wide angle prime/zoom or telephoto prime/zoom is just one of the determining factors of a lenses construction. Others being its focal length(s) and zoom range. If there are too few elements and groups the final image may have many optical aberrations. If too many elements and groups there could be a lot of flaring in the final image. The engineer must find a good medium between too few and too may elements and groups.

2. Personally… there is no minimum/maximum number of elements and groups in a lens that I look for. As long as the lens produces sharp images, renders color nice and true and produces good(in my eyes) bokeh I would be interested in it.

3. The pairings of elements(just like single elements) are designed in such a way to minimize or eliminate a specific optical aberration. For instance… Chromatic Aberration or “Color Fringing”. To get rid of this an engineer may take two elements made of different glass compounds and different refractive indices and cement them together to form a pairing or group designed to do this. This may also be done to minimize or eliminate Spherical Aberration, Coma problems or any other optical aberration.

So for your comment about only using one larger piece of glass instead of two… if that could be done I imagine engineers would do that. But it can’t. To get rid of specific optical aberrations different compounds of glass with different refractive indices, molded in a specific way, cemented together and with certain coatings must be used.

Wandering My Garden In The Dark

It’s been raining for almost two weeks and I wanted to take some pictures. Nikon’s D90 does not like water so I’ve been waiting until the rain subsides to take pictures. Unfortunately, this has been at night. In the past couple of days I have learned that taking pictures at night is a true testament of what you know and what you don’t know. Well, tonight I learned mostly about what I don’t know. Taking photos in the dark is all about TRIPOD, TRIPOD, TRIPOD!!!! Did I mention that you need a tripod? Oh, and you’ll also need a TRIPOD! A remote comes in handy, too. I’ve got Nikon’s handy-dandy ML-L3. It works like a charm and is the best $20 I’ve spent is quite some time……… Except for the really cute sandals I purchased last week, ……….oh and the belt.

The picture that I took tonight is part of my photostream. It’s an allium. There are some parts of the flower that are blown out, but oh well. I tried. Memo to self: Turn down ISO a little bit when there is lighting in the background.

I don’t want to seem like the blind leading the blind, but I would like to shamelessly plug Gorillapods! WooHoo! Pretty kewl invention. It’s nice to have a tripod that I can bend into whatever shape I need. Go out and get one folks! Use coupon code: SMUGMUG and get $10 off while it’s still being offered!

D90 Takes On DWB!

DWB: Driving While Black, is a common crime in the United States for many African Americans. It is not uncommon for African Americans to be stopped by the police for no reason and given a ticket. I know what you’re thinking, the cops would never do that, right? Wrong! Happens to my people daily. What’s even more disappointing, is that there is no recourse. Police Officers are ALWAYS right (you learn this when you get to court). Ask anyone who has been to traffic court without an attorney. If you play the game (don’t pay your rent so that you can afford an attorney), and go along with the racket, your chances of vindication are better. Go it alone, and they nail you to the cross.

Today, as my husband trailed behind me on his motorcycle through a residential area, and a police officer followed us the entire two miles. Initially, the speed limit was 35mph, then 25mph, 15mph, and then finally 10mph. I was very careful not to exceed the speed limit, as I knew that the officer was simply ‘looking for a reason’ to stop us. With my leading us, would have proof that the officer stopped us for no reason.

Upon making our final turn onto the 10mph stretch, the officer turned on his lights and pulled my husband over. He had no reason for doing this. My husband and I both pulled to the side. I got out of the car and immediately started taking photos. The officer seemed alarmed by this and asked my husband, “Is that your wife? Why is she taking pictures?” He then asked my husband for his license and registration and went back to his car. Within seconds, he returned from his car and told my husband that although his registration showed that his motorcycle is registered through 2010, DMV records had information stating the contrary and that his registration had expired December 2008. He told my husband that he should contact DMV immediately to clarify “their error.” Well, this is exactly what we did. We immediately went to DMV and they could not validate the information that the officer ‘alleged’ to have received from them. Their records concluded that my husband’s bike is registered through 2010. The officer lied to save his own ass, and my D90 saved the day!

I think back to something a fellow photographer wrote not so long ago, “I don’t see color.” My response is still, “You’ve never had to.”