JPG versus RAW

I wanted to take a photo for the Flickr D40/60 Challenge group I belong to. The challenge topic was Silohettes', seeing nothing of interest around the home place I decided to run up the road to my grandmothers farm. It was a very overcast day which should make silhouetting very easy but I kind of wanted some blue sky.

I walked into the old tobacco barn thinking it might make a neat silhouette shot from the inside. After taking a few shots and looking at the results in camera I decided that they just didn't look good. It hit me that this would be a good opportunity to get some shots to do some new RAW versus JPG comparisons.

I used to used to shoot RAW a lot since reading about so many saying how much better RAW is. I got tired of spending so much time messing with RAW data and finding my printed RAW photos look no better than JPGs. The software developer in me started to say why do I not see any difference in prints.

I started looking passed everyone saying 'RAW is great' and 'all of the pros use i' wondering just why I don't see any difference. Everyone is saying that RAW has so much more data, 12 bit versus 8 and that you can fix badly exposed shots. After googling around for quite a while and reading a lot of technical articles I concluded that RAW does nothing for you and it is probably mostly driven by marketing and peoples lack of knowledge. I went back to shooting JPG and have never looked back.

In a nutshell I discovered that 8 bits can represent more shades of each color than we can actually see, all printers that I may ever have my work printed on are 8 bit, Nikons RAW data format is proprietary meaning that everyone but Nikon has to guess at how to decode it, the RAW data format changes with each camera version and 20 years from now we may even have no way to view the data, all RAW files need processing (basically converted to JPG) to see or print, operating systems need third party software just to view.

Anyway, below is my post processed out of camera JPG from my D40 with all in camera processing functions set to manual and a RAW. Above is the out of camera JPG with no post processing down sized by Irfanview. Camera was in manual exposure set the same for both shots and it's obvious I didn't use a tripod.

I didn't spend more than 30 minutes or so on both shots, I used CS3 camera RAW on both. Which is the JPG and which is the RAW?

Polarized City

Louisville - No Polarizer 8-8-8
Originally uploaded by mmikee

I went out on a nice clear evening last week to see how the setting sun might be reflecting off the buildings of downtown Louisville, KY this time of year. There were no sun reflections but while there with camera in hand I thought I would take a few shots. I liked the way the clouds were hanging on the east side of the buildings.

I mounted the D40 on the tripod with the 18-200VR attached. I took a few shots and then wanted to add a polarizer to deepen the blue sky, since the sun was to my right I thought I would get lots of blue.

Louisville - with Polarizer 8-8-8
Originally uploaded by mmikee

I was really quite surprised when I got home and saw the actual differences between these 2 shots. Usually the polarized shot is way better than the non polarized, here I am not sure which I like better.

Can you tell which photo is polarized? Which do you like better?

Wide Angle Lens Polarizer Thickness

A question came up in the Sigma 10-20 group about circular polarizer filter (CPL) thicknesses and there vignetting effects. Since I have (was told I needed the thin one) for this lens and I had just recently purchased the same 77mm CPL in normal thickness I thought I would do a quick test.

Below are 3 photos I took with no CPL, thin one and thick one. While not a great consistent background, shooting at 10mm requires a lot of scene, it was hard to find anything better this evening. I might retake some photos on a clearer day when I can get into a more open area.

Sorry, I didn't drag out the tripod. Exposure for the CPL shots was set to the same as the non CPL shot. I let you judge for yourself the results but it appears thick CPLs are just fine.

I'm still figuring out this blog stuff so please pardon my ignorance on posting photos in the blog.


No polarizer


100$+ Tiffen Thin Polarizer



29$ Sunpak Thick Polarizer

Moving the Blog

Ok, so I had a blogger account I have not kept up with and had it setup for pre shotsbymike.com, it was pointing to mikeschellenberger.com I wanted to keep the site as is but just make it belong to shotsbymike.

Once I remembered the login for the old account I had to add my new blogger account as admin to the old then remove the old account from admin. Not to bad with blogger help just had to log out and back in to both accounts a number of times.

Next I needed to remove the old blog.mikeschellenberger.com URL redirect to blog.shotsbymike.com. Went to my mikeschellenberger.com host account and removed the CNAME entry then added a new CNAME entry to shotsbymike.com. My hosting site, WebHost4Life, says it takes an hour for the CNAME to take effect.

I am writing this working on killing an hour and hopefully, shortly, my blog will be at blog.shotsbymike.com

Now I must go and request the fix for my Sirius radio. Since the Sirius XM merger, Sirius decided to lower the FM output power of my receiver to be within FCC specs. For 2 years they have been transmitting to much power, wondered why it was always so hot, the fix now makes the signal to my car radio noisy to unusable sometimes.

Nikon Strobe Info

I extracted the following from a Nikon support document

The following strobes support these modes on the D200, D80, D70s, D70, D50, D40

SB800
i-TTL, Auto Aperture (AA), GN, Auto, Manual, Rear Curtain, Repeating Flash, Red-Eye Reduction, AF, Zoom

SB600
i-TTL, Manual, Red-Eye Reduction, AF, Zoom, Rear Curtain

SB400
i-TTL, Manual

i-TTL
The camera controls flash output. This is a TTL auto flash mode in the Creative Lighting System. Monitor Preflashes are fired at all times. The subject is correctly exposed by the light from the flash and the exposure is less affected by the ambient light than in the conventional TTL mode.
Supported cameras: D2X, D2Xs, D2H, D2Hs, D200, D70, D70s, D50, D80

i_TTL as described in Nikons CLS document
Monitor pre-flashes are emitted from a Speedlight before the main flash and reflected off every object in the frame. Monitor pre-flashes are picked up by either the five-segment TTL flash sensor or an RGB sensor. This information, along with data from the Matrix Metering System is analyzed to adjust flash output for the most balanced background/foreground exposure possible.

Exposure - The Confusion Factor

I hope we are not moving to fast here but we should all have a pretty good grasp on how exposure is controlled. Another quick overview, we have 3 things on the camera to adjust to effect exposure aperture (f-stop), shutter speed and ISO (light sensitivity). When taking a photo we can let the camera's auto modes choose all of these settings, we can set all or some and the camera will set the others. The camera uses the built in light meter to determine the settings it will use.

I just realized I'm wrong when saying that there are 3 things on the camera used to effect the exposure. Indirectly there a more ways to alter the exposure but on camera a fourth way to effect exposure would be the camera's metering mode. The various metering mode's interpret the light in the scene differently. The use and effects of the different modes will be covered in a future article. The default matrix metering mode attempts to be intelligent and compares current readings with what Nikon has programmed into the camera and the camera will set the aperature and shutter based on this. Most of the time this 'intelligence' works pretty good but the problem I have is that I really never know just how that intelligence is going to set the camera for my next picture. While on this topic I might also add that we can also indirectly effect exposure outside the camera by adding filters or controlling light that is in the scene.

Confusion Factor
In the last article I introduced the standard set of f-stops 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32. The f-stop is our aperture measurement and remember a bigger aperture, opening in the lens, lets in more light. Now for the confusion factor, the actual size of the opening in the lens (aperture) is inversely proportional to f-stop numbers. So, f/1.4 is a bigger aperture opening than f/2. There is 'scientific' reasons that they are backwards but we won't go into that. You just gotta remember if you want more light to get in the camera, you need a bigger aperture opening which means a smaller f-stop number. It takes time but will sink in. Also remember that opening the aperture, smaller f-number, will decrease the depth of field.

Stop Down
If you read much about photography you will frequently come across the term stop down. When you stop down a lens, you are going to a larger number/smaller aperture and therefore less light. Changing an f-stop from f/1.4 to f/2 is referred to as 'stopping down'. The opposite is opening up, going from f/2 to f/1.4 is moving towards the smaller number/larger aperture and therefore more light.

So now hopefully we all know, or are at least getting a grasp on, the basic mechanics that cameras use to control exposure. In order to take your photography to the next level you must understand these basics. If you just leave the camera in auto mode all of the time you will get good pictures a lot but not all of the time. As you get more experience you will start to see some particular lighting scenarios where the camera goofed up, this is where your knowledge of exposure will start to come into play.

While writing this article I came across a dated but very easy to read site that goes into slightly more detail than I have here. If you want to dig a little deeper or read from a different view point here is the site.

Whats Next
Now that we know what all goes into exposure the next step is to learn when we need to step in and change the exposure for our current scene. In low light we need to make sure the shutter speed is fast enough to not blur movement, in an action shot we must make sure the shutter speed is fast enough to stop the action, if so desired. In a landscape scene we would probably want a large depth of field which means a smaller aperture, bigger f-stop number. While photographing a single person in a crowd we will probably want a shallow depth of field so we will 'open up' by larger aperture, smaller f-stop number.

RTFM - Read The Freakin Manual
So for now pull out the manual, look at how to change the ISO, set the shutter speed and aperture. Get familiar with how to get to the various settings I have talked about so far. Check out the different metering modes by taking some photos of the same thing in various modes, a back lit or scene with a lot of contrast will be particularly reveling in comparing metering modes. Take the camera out near dusk and change the ISO settings note how this effects the shutter and aperture speeds chosen by the camera. Take a picture looking down a fence row or for city dwellers a line of parked cars, change the aperture and note the effect.

I think the next article will be on white balance, check that out while you have the manual out. Luckily, the D40 does a pretty darn good job at white balance in auto mode but there are times when you will want to change it. Til next time get the camera out and play with it, all it costs is time.

Exposure - Getting Technical Now

Ok, so now hopefully after the first article on Exposure you have the concept of how the camera controls the amount of light exposed to the sensor. A quick refresher, a bigger hole in the aperture means more light and less shutter open time for same exposure as a smaller aperture opening and longer shutter open time.

Camera Meter
The cameras metering system is responsible for figuring out how much light it thinks is needed to properly expose a photo. In all modes but manual (M) the camera will always set at least one of the 3 things it can set to make what it thinks is the proper exposure for the current scene. There are various metering modes and they all effect how the camera actually figures what it thinks is a correct exposure for the current circumstances. I have a future article in mind for this topic alone but for now we will just stay in the default matrix metering mode.

Astute readers may be wondering what the 3rd thing is that the camera can change, that would be ISO and it is basically a light sensitivity setting. The higher the ISO setting the less light it takes to make a proper exposure. It doesn't come for free however, more sensitivity brings more noise into the photo. So we now have another choice when it comes to getting a proper exposure. This choice is typically along the lines of, I don't have enough light under the current circumstances to make the photo so I must up the ISO. Sometimes there will be enough light for a properly exposed photo but we need a faster shutter speed because we have things moving in the picture and we don't want them to be blurred. In this case again we can up the ISO, this will allow us to use a faster shutter speed because we now don't need as much light for a proper exposure.


Camera Modes
The camera's various full auto modes will set both aperture, fstop and sometimes ISO as it desires. In P, S and A modes you can effect either the aperture or fstop used and the camera will automatically select the other setting to make the exposure as the camera thinks it should for the current ISO setting. Actually, P mode you effect both shutter and f-stop, more on that later. In full manual mode, M, you set both shutter and aperture as desired, in this mode you can, and should in most cases, use the exposure meter for reference. The camera's exposure meter is still measuring the scenes light and the metering bar tells you if it thinks you will over or underexpose the photo and by how much for the current fstop, aperture and ISO settings you have chosen.


F-stop's and Shutter Speeds
Finally I we must introduce the actual f-stop numbers and shutter speeds. I'm not going to get anymore technical than need be here, you can find much more detail if needed via Google. The camera industry long ago derived a standard set of f-stops as follows 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32 that go along with a standard set of shutter speeds 1, 1/2, 1/4, 1/15, 1/30, 1/60, 1/125, 1/500, 1/1000, 1/2000, 1/4000, 1/8000, 1/4000. These f-stops and shutter speeds are in what the industry calls 'one stop' increments. Most all cameras now days have these number in 1/3 stop increments so there is probably 2 numbers between each of these standard stops on your camera. i.e. going from f-stop 2.8 to 4 is one stop but in 1/3 increments we have 2.8, 3.3 and 3.5 before we get to 4.

The beautiful thing about these 'standard' f-stop and shutter speeds are their relationship. You can derive the same exposure by changing either the aperture or f-stop by 1 (or more) stop(s) each. Lets say for a photo we want to take, the camera metering system tells us or auto mode has chosen, f/8 @ 1/250 as the exposure for the current scene. We can alter the look of the photo by choosing a new f-stop and aperture, all we have to do is change each by the same 'stop' amount. An exposure of f/4 @ 1/1000 will provide the same exposure as f/8 @ 1/250, the f-stop went down 2 stops and the shutter speed went up 2 stops.


Whew....
I hope we didn't get to technical here, I will end this article before we get brain overload. In quick summary, exposure is effected by 3 things f-stop, aperture and ISO. A higher ISO means it takes less light for an exposure at the expense of more noise in the photo. F-stops and shutter speeds have a corresponding relationship, the same exposure can be had by various combinations. Knowing the effects of the various f-stop and shutter speed settings is what will let us alter the effects/looks of our photos.

Please post comments, questions or mistakes in my writings to this in the D40 Plus groups thread on this article.