Results tagged “technique”

Colour to Black & White?

In camera, or post-production?

Recently in a flickr discussion forum, the issues of in-camera processing came up. LotF, the photographer in question, was disappointed at the results his new camera was producing, with in-camera b & w conversions, compared to an older camera. Some argued that it was the camera, or maybe the camera's software. Others also wondered out loud about the pro and cons of in camera conversion and post production conversion.

I am a fan of being aware of and able to control outcomes to meet my expectations, this is something any software that is fully automatic will lock the user out of entirely. Therefore I tend to avoid in-camera processing, besides it's almost impossible to make good judgments on a screen that small.

So, for me the only way to convert is in post-production. I did however conduct a small simple test, one shot as usual and then the same shot with the camera set to b&w*

I used Photoshop's black and white conversion on the default settings. image>mode>black & whiteThe results indicated to me that post was indeed better. Subtle but better. [The in-camera shot for comparison.] The highlights were over-exposed, the shadows and mid-tones were ok though, I guess if you had the software to run a jpeg through a raw conversion tool, you could fix up some of the problem areas and blend them together.

original file converted post exposure

This in camera processed shot, has blown highlights and poor mid tone separation, the contrast seems to high too for my liking.


in camera conversion

Post processed has more values to work with, the shadows reading #3, are little empty for my liking though, easy fixed with some tweaking in Photoshop.


*This has all been done using phone cameras for speed and convenience.

Photoshop Layers 4

Layer Masks, one of my favourite tricks is to duplicate a layer, make some changes to it, whether it be colour contrast b&w, or some other effect I want to, apply to the image then add a layer mask and brush in any differences I want to see applied to the image.

Using a black and white image on top of the other is one of the most common, but intensifying colour using curves or levels is one of my favourites. Again this approach in non-destructive, and infinitely un-doable, while the layers are unflattened.

Lastly the Text Layer, which is relatively self explanatory, I hope? Handy for adding a copyright watermark to your image I guess?

Photoshop Layers 3

Today, I'm going to look breifly at how I use adjustment layers.

From Photoshop's help files:-

An adjustment layer applies color and tonal adjustments to your image without permanently changing pixel values. For example, rather than making a Levels or Curves adjustment directly to your image, you can create a Levels or Curves adjustment layer. The color and tone adjustments are stored in the adjustment layer and apply to all the layers below it. You can discard your changes and restore the original image at any time.

As a small aside you can now access an extensive set of help files on the web directly from the help applicaiton in photoshop.

The key issue here for me is the ability to make and adjustment to say colour balance density or saturation of an image and then brush through the mask to locally adjust the image to best suit my ideas and intentions in photograph.

This approach offers a degree of control unheard of in the history of colour photography. Combined with a desktop inkjet printer like the Epson R2400, I now have a complete home colour darkroom. And of course, again, no pixels are destroyed in the process.

adjustment layers

Processing Matrix

Here's a Downloadable pdf of the processing matrix, that may be easier to read.

1/2 Done

IMGP1471.JPG

I shot the first half of the DOF exercise on Friday. I used a zoom and a fixed lens. Just looking at the lens markings on the zoom confirm yesterday's post.

The second half requires either a portrait or a still life.

The reason we use either a portrait or still life is, because when the subject is closer than 8 times the focal length of the lens the relationship of f/g and b/g DOF changes.

The top image was made using the fixed 50 mm lens, which actually has an equivalent 35mm focal length of about 80mm

Here are the two lenses used, it's interesting to notice that, the Zoom lens made for the Digital camera, has a smaller spread of distances under 1 metre than the fixed lens.

2 Lenses

Realisations

Yesterday at work, we were discussing an exercise the students undertake to understand Depth Of Field.

Historically, we get them to take 1 shot at 3 different apertures in one location on a tripod then shift focus and repeat, finally focusing on infinty and repeating again, as well as a portrait at 3 different apertures, on a tripod.

A year or so ago I did this exercise using a Canon 350d, and the differences were NOT as apparent, as a traditional 35mm camera, I left it at that and haven't given it much thought since.

When I mentioned this in the meeting a passionate discussion then ensued as to why this was the case as we are contemplating getting the students to do this assignment using digital cameras. Beginning students need to see big differences quickly and the 350d wasn't giving the results I'd expected.

As a result, we found the answer. It has to do with surface area of the light capturing surface and size of circle of confusion. The smaller the film/sensor area the more D.O.F you have.

Let's let Bob Atkins explain it.

"So the bottom line - and all you really need to know - is that DOF is inversely proportional to format size. Note that format size is inversely proportional to the "digital multiplier". The higher the "digital multiplier", the smaller the format and thus the greater the depth of field. Note also that now you can see one of the reasons large format camera users need tilts and swings to get adequate depth of field. With an 8x10 camera you have about 8.5 times LESS depth of field than you do with 35mm for the same image. This also explains why consumer digicams, some of which have sensors 1/6 the size of 35mm film, have such a large depth of field and one of the reasons why it's almost impossible to get blurred backgrounds when using them."

The difficulty for us to teach the principles of D.O.F is that all cameras have different sized sensors and only cameras like the $4,000.00 Canon have 35 x 26 mm sensors. A camera few students can afford and the type that is not held in stock by us because of their delicateness.

Today I am going to shoot the exercise on the Pentax k100d, which has a larger CCD than the Canon 350d. I may post the results over at flickr, we'll see?

Some more links:-

Photographic Memes

So, in the nealry 2 years I've been involved with flickr I've seen several memes come and go, the current one HDR, sadly shows no sigh of abatting. The newest kid on the block on the other hand, is "Through the viewfinder". Some interesting results, and a nice idea that if elegantly applied could produce some great results. Even Kottke is waxing lyrical about it the idea of digitally capturing a scene though an old camera.

Some flickr clusters on the matter.

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