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Coffee filter white balance

29-Dec-09

Coffee filter white balance

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Coffee filter white balance trick

Some of you already know this, (Coffee filter white balance) but for those of you that don’t, I am about to make your day.

You can buy a tool such as an expodisc for about $100, and carry it in your camera bag, or for a few cents, and the ability to wad it up in your pocket, you can use a standard coffee filter (the white ones). You could also place a gray card in the scene, but sometimes you can’t such as stage performances, big parties, weddings etc.

Hey, I shoot raw, why does this matter?

Answer: It really doesn’t, but it is much easier to start out with the correct color, than "eyeball it" later. Another important matter I found out this Christmas is shooting video, you can’t easily correct the color in a couple gigs of yellow cast video you shot indoors. Also, if you shoot jpeg, this will be your new trick to fix all the yellow indoor shots as well.

Ok, How do I do it?

Answer: Very easy, most cameras have a custom white balance function that let you sample one of the shots on your card that you just took.

Procedure: You just hold the coffee filter snuggly (or use a rubber band) over your lens, and point your camera at the light source (one of the lamps in the room etc), and shoot one shot. Then you go into your menu, and select that shot as the custom white balance shot (practice first, I know with Canon, you need to set the white balance to custom in addition to, and after choosing your custom shot), and voila, your scene is near color perfect. This is not perfect, but in my tests, it is pretty darn close, and to the naked eye, I can’t really tell much difference.

I have included the before and after shots in full res, and the coffee filter shot as well for your reference.

HERE ARE ALL FOUR RAW FILES

First shot with no correction, right out of the camera:

Before

The coffee filter shot:

Coffee filter shot

The corrected shot after using the coffee filter shot as the custom white balance:

Coffee filter white balance

Same shot with a gray card for reference: (gray card was not used for white balance, just placed in the scene for later analysis, and for you to see how close the coffee filter is)

Gray card for reference

HERE ARE ALL FOUR RAW FILES of the Coffee filter white balance shots. I hope this article on Coffee filter white balance helps someone, have a great day!

Tags: coffee filter white balance trick, how to

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Protecting your camera this winter

29-Nov-09

Protecting your camera this winter

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Yes, it snowed in Moreno Valley, Ca.

Taking your camera out in the cold weather is not really a problem, as a matter of fact, your camera will operate just fine. The problem arises when you come from the outside back into a warm room. If you change the surrounding temperature from cold to warm, condensation builds up on every surface, both external, and internal. This happens inside both your camera and lens. This is how mold, and fungus grows inside lenses and cameras.

From Cambridge in Colour Forums:

The main thing to worry about is protecting your camera/lens from excessive condensation. This will occur whenever a much colder item is moved into a warmer environment.

Understanding why this happens is the key to preventing it. Condensation occurs because cold air is unable to contain anywhere near as much vapor as warmer air. When the warmer air comes into contact with a cold surface, this surface cools the air. Unfortunately, warmer air contains far more water vapor than cooler air (at the same humidity). If the cold surface causes rapid cooling (and/or the humidity is high in the warm air), then the cooler air will be unable to still keep all the water as vapor — causing it to condense out as droplets on the colder surface.

Condensation is much more pronounced for camera lens elements (and anything else metal or glass) since they have a much higher thermal conductance. This means that metal/glass cools air which comes into contact with it much faster. The camera sensor and other internal electronics also have high thermal conductance, but they are a little less susceptible since they are not directly exposed to the ambient air. This results in a buffer zone of air with an intermediate temperature within your camera body. If this buffer air is completely isolated from the outside air, then condensation will not occur. Sadly, this is rarely the case with all but the most weather sealed cameras/lenses — meaning that internal condensation can still occur for high humidity or large temperature differences. This kind of condensation is particularly problematic because it can take a lot longer to dry out.

Fortunately, there’s an easy way to prevent camera/lens condensation: *before* taking your camera/lens into the warmer environment (aka indoors), place all items within a plastic bag and ensure it is sealed airtight. You can then take these sealed bags indoors, but you have to wait until everything within the bags have become thermally equilibrated with the indoor temperature before you open the bags. For large camera lenses with many elements, this can take 30 minutes or much more if the outdoor temperature is very low. The process can be accelerated substantially if you first remove the new camera and/or new lens from their boxes, before placing them in the sealed plastic bag.

However, condensation is not necessarily the only worry. If the temperature of your camera and/or lenses change very rapidly, then they will unavoidably undergo thermal expansion (when going from cool to warm). The problem is that glass lens elements, plastic, rubber and metal all have different coefficients of thermal expansion. This means that they expand/contract different amounts for a given temperature change. Ordinarily this should not be a problem since a good camera manufacturer accounts for a reasonable range of operating temperatures in their design. The precise position of infinity focus will noticeably change in cold versus warm weather, for example, but this never noticed when using modern autofocus mechanisms. To me, thermal expansion seems like it could only be a problem in the context of lens/focus alignment — if somehow the position of elements moves permanently (relative to the lens encasing) as a result of some drastic and rapid temperature change. Never heard of this being a major issue though. Just make sure that you do the “bag trick” above, and it will have the side effect of also dramatically slowing the rate at which your camera equipment warms up. As long as you prevent condensation I would not worry about this second problem.

Tags: camera maintenence, cold, winter

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When in Rome…

22-Nov-09

When in Rome...

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I thought I would share a tip; when you are shooting an event, always try to shoot what is around you and right in front of you. We always concentrate on the event, but it helps to tell a story. Take shots of the location wide, then closer, then inside the venue, then the audience etc.

Wedding photogs are pretty good at this, but it is a great tip for all of us.

Here are shots from the event last night.

BTW, the Canon shot long, and the Nikon shot wide. I prefer the Nikon’s pixels from this event.

Sierra Springs Talent Show-53-Edit

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Sierra Springs Talent Show-528-Edit

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Tags: Canon EOS 5D Mark II, events, Nikon D3

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Nikon D3 sensor cleaning – don’t do it yourself!

19-Nov-09

Nikon D3 sensor cleaning - don't do it yourself! Much love for the Nikon guys

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I pride myself in being pretty handy with most normal maintenance requirements that my photo gear may need. I have cleaned all of my Canon sensors many times with no problems. With this in mind, I decided to pop open the mirror on my D3 and clean the sensor the other day. My blood pressure, and heart rate were normal as I started, but this quickly changed… to almost a panic.

I swabbed the sensor as I have done for years with a sensor swab, and popped my lens back on to check it (shot the sky at f22… the normal check). I then checked the image in Lightroom, and it was worse!…. what the.. ! I tried it again, this time with an LED light to see the sensor while I was cleaning it. This time I noticed what the problem was. I was not able to clean the edges without leaving some residue, and this was causing the problem. I tried a few more times, and the same thing kept happening, still dirty!. I finally gave up and decided to drive the camera to El Segundo, Ca, and drop it off with Nikon. I figured if I can’t do it, then no counter guy at any local camera store could do any better, so I should take it directly back to the factory.

_DSC1363

I drove out to El Segundo shortly after my panic had almost set in, and after an hour or so on the freeway, I arrived at the Nikon headquarters and was greeted by a warm and friendly feeling staff. They told me it was only $28 to clean it, and it would be ready in 24 hours! I was shocked at how cheap it was because I have seen my local guys charge $60 for the same thing. I left the Nikon facility with a better feeling and my Canon (5D Mark II) gear still intact, so if I wanted to shoot something I could. You should always have two bodies, but not to side track this post, I will keep going.

The next day, I planned to pick up the camera, and make the same drive again. I called my friend Mike, and asked him if he wanted to drop off his camera (he had a loose lens release button that started at the camera show the day before) at the same time for him. Like a father dropping off his kid at school for the first time, he gave me his camera, and told me to take good care of her. I drove straight to El Segundo (not wanting to stop, feeling like I had extra precious cargo with me. Ever have that feeling of caring more for SOMEONE ELSE’S gear?), and arrived without almost any traffic. I told the Nikon guy what the problem with Mike’s camera was, and he wrote it down, and disappeared behind the door. he came back, and told me that he would have the repair for Mike’s camera done under warranty (Mike’s camera is way out of warranty) as a courtesy. I also asked him to clean Mike’s sensor as well.

My camera was ready, so I took it out of the neatly wrapped plastic bag it had been stored in, and there was a paper attached to it saying that Nikon had updated the firmware as a courtesy, and they had also clearly cleaned the body. I was so impressed! I had that dealing like I had just picked up a mercedes with a chocolate kiss left on the dashboard. How cool is that? You might think that it is not really a big deal, and well… it isn’t, but how many local camera stores have this level of service… for $28?.

_DSC1368

I took the camera outside, mounted my lens, and shot the sky at f22, and thought I still saw something in the corner. I marched back in expecting some arguing, but instead was greeted by the head tech, who gently told me, “Don’t worry, I’ll check it right away while you wait.” I waited for 15 minutes or so, talking to other Nikon owners in the room, and then he came back out with my camera. He showed me images he had just taken, on a monitor, and let me look over the image myself, and I did. Everything looked good, so I thanked him very much for the personal attention. I asked him why I had trouble cleaning it, and instead of the factory rhetoric about how you should never clean the sensor yourself, he explained that even Nikon’s own techs have trouble with this camera because unlike other Nikon cameras, this sensor has no voids, or grooves around the sensor, and since the fluid has no where to go, every time you lift the swab off the sensor it may leave residue. He said they worked on my camera (and other D3’s all the time) extra to insure that it was clean.

For this reason, I will ship my D3 directly to Nikon ($12.50 each way beats driving so far) from now on for sensor cleaning, and you should to. You cant beat this level of service for $53 with shipping both ways.

Tags: Nikon, Nikon D3, sensor cleaning

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Digital is not yet where it should be

29-Oct-09

Digital is not yet where it should be

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This photo is from an 18.9 megapixel scan of a slide taken in December 2001. This represents the max resolution that I can get out of my Nikon Scanner.

35mm slides were the best way to shoot back in the day, because you could scan to any size you wanted. Well today, I think we have reached a point where film (at least 35mm anyway) is no longer a viable tool. Most photography classes start out in film, which I think is good (teaches correct exposure etc), but other than nostalgia, 35mm film is done in my opinion.

4×5 film is another story, and it may be quite some time before I surrender my 4×5 gear. Right now I can shoot a cleaner sunrise shot with my 4×5 than with any digital camera. I am going to shoot with the Hasselblad H3DII in a few weeks for comparison, and I will let you know.

I use the word "clean" because now that the megapixel war has plateaued (not over), the camera manufacturers need to work on cleaner images. There is still lots of noise they can clean up in my opinion. The sunrise shot I took last week has lots of noise in the deep blues of the morning sky that is not present AT ALL in my 4×5 film shot.

I actually I am pretty dissapointed in my 5DMKII. I have also tried the Nikon D3 etc, so it is not the brand that matters, the technology is just not there yet for high quality shooting. Most of you will argue that it is "good enough", and I agree, but let’s keep pushing the smart guys at Canon and Nikon to come up with even better sensors.

Check both of the shots below, and I’ll let you guess which one is the 4×5 shot. Early morning deep blue is the hardest color for digital cameras to reproduce in my experience, so this is a great comparison. These shots were not taken at the same time, and that is the reason for the color difference, but you can clearly see how clean one of them is.

This may cause some of you to ask where you can get a 4×5 camera, and the answer is Ebay, and they are cheap in comparison.

The 4×5 was drum scanned.


Tags: 4x5, 4x5 film, digital slr photography

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