Showing posts with label sharpness. Show all posts
Showing posts with label sharpness. Show all posts

Thursday, June 21, 2012

On the Range...

Greetings, volks. Welcome to Hohenfels Volks, THE place for our place! Today’s weather turned out to be quite nice. There is a wide variety of things and places to shoot in our little part of Germany. Clouds and fields are just coming around to being incredibly photogenic.

Today we’re going to take a quick look at contrast and exposure. When we refer to contrast, we’re generally speaking about the range of values within an image or scene. From the brightest areas to the darkest is our range, and the contrast ratios can be quite high for a full range scene to rather low for a lower contrast image, such as a portrait.

As a general rule, higher contrast images tend to be more dramatic, while lower contrast images run toward the softer side. That’s the reason we call lower contrast “softer.” An image’s sharpness is also dependant upon contrast. When you decrease contrast, you can quickly decrease sharpness if your not careful.

Contrast can be varied by exposure. When an image runs toward high key, it loses contrast due the lower values being absent. The inverse is true in low-key images, though to a lesser extent. By adding shadow and decreasing brightness or overall exposure, contrast can apparently be increased. Decreasing exposure by 1/3 stop can be just the trick. The same can be said for color contrast, which is the range of tones in a single color within your image.

Drama can be added through darkening, and tranquility, or stillness, through lightening. Local contrast can be adjusted within a narrow range of tones, improving appearance, detail, and bringing interest to an area within the image. By using levels for general contrast adjustments, and curves for local effects, an interesting image can be created.

Combined with visualizing the desired outcome, or range of outcomes, limitless possibilities exist within each image. By exposing your brightest areas for M+2 and your darkest for M-3, a visual feast can be created from one shot, if done right. Visualize the effect of several adjustments and contrast ranges, and then set the shot so that each one can be accomplished using limited adjustments.

I hope this gives you something to think about and play with. Throw in some work with this week’s exercise, and you’ll be sure to get something that fills with that pride of accomplishment that comes from a shot well made.

Take care and enjoy the rest of the week!

Is there anything you’d like to see here? Do you have a question? Share your thoughts here or at the Hohenfels Volks Facebook page. Of course, commenting on both Facebook and here is always appreciated, too! Don't forget, we're on Google+, too!

Monday, June 11, 2012

Tools of the Trade: Our First Review...

Greetings, volks. Welcome to Hohenfels Volks, THE place for our place! Another busy week in Hohenfels left us without short on posts, but more will come! I trust all are well and enjoyed some shooting time this weekend!

I went out shooting Saturday to test the Tamron 28-75 1:2.8 lens. This fast shooter was a nice break and allowed for some shallow DOF and creative shots, as seen in the shots below.

Hohenfels Volks: Cupcake
ISO 125, f/4, 1/400
Cupcake and icing. This cupcake was about 2 inches across, shot at 70mm with a wide aperture created some nice blur and bokeh.

Hohenfels Volks: Fruit Salad
ISO 125, f/8, 1/100
Fruit bowl. Great colors and even with f/8, at 75mm the DOF is shallow enough to be creative.

The best feature of this lens is the constant aperture throughout the entire zoom range. F/2.8 is nicely fast, and allows a nice low light performance. It also allowed some creative shots that really emphasize DOF effects to highlight part of a scene.

The lens is lightweight, and focuses down to about 13 inches at all zooms. The zoom lock feature makes a nice addition for when you’re moving around with the camera pointing down. The filter size is 67mm, which is large enough to prevent vignetting unless you’re stacking filters and shooting at 28mm.

The lens does not rotate or extend while focusing, which simplifies the use of a CP. Rotating lens barrels often necessitate adjustment of your filter after focusing. The images were sharp through all focal lengths, even wide open. Where you focus will be tack sharp when used properly.

The big downside to this lens is the lack of image stabilization. This saves battery life, but has its own drawback. When you’re shooting handheld, you have to shoot faster than the reciprocal of your focal length. If your focal length is 50mm, than you have to shoot at 1/50 or faster. With an APS-C sized sensor, the focal length has to be multiplied by 1.6 to get the corrected number. For those with APS-C sensors, this means shooting no slower than 1/50 at 28mm. While this little champion performs well in low light, being limited to faster shutter speeds may be a drawback when shooting inside places without adequate illumination. Camera shake becomes very noticeable, even in smaller display sizes, at slow speeds and may lead to some seeming nice shots having to go into the dustbin.

Another drawback to the crop factor of the lens is DOF calculations. You will need to calculate based on the original focal length, not the cropped focal length. This can lead to a DOF you may not desire. This is usually not an issue, but could lead to shallower depth than you find desirable.

With most of today’s cameras capable of giving good performance at 1600 ISO, the lack of IS may not be an issue, but in a church or other extremely low light venue, not being able to handhold is a real setback. Overall, this lens is wonderful, especially in reasonable light. The image quality is spot on. There is no noticeable chromatic aberration, color reproduction is wonderful, sharpness is very fine, and there are no color shifts often seen with lesser lenses. Tamron makes some great stuff, they also make some lower end stuff, but this lens is one to get if you don’t mind the limitation in lower light. I didn’t get the chance to push it too hard, it’s not mine, but the little workout it received proved it a worthy addition.

On other issues, has anyone had the opportunity to get out and make some storm cloud magic? The weather has lifted bits here and there to allow some great photos to be made! Give it a try. Remember to meter for the entire range, and expose for the brightest parts you desire detail at M+2-M+3. You’ll be surprised at your magic!

My thanks to Darris for allowing me to test out this little giant of a lens. Here’s hoping everyone out there has a wonderful week and makes your photo dreams come true!

Is there anything you’d like to see here? Do you have a question? Share your thoughts here or at the Hohenfels Volks Facebook page. Of course, commenting on both Facebook and here is always appreciated, too! Don't forget, we're on Google+, too!

Tuesday, April 17, 2012

Ambience...

Greetings, volks. Welcome to Hohenfels Volks, THE place for our place! This time of year in Hohenfels starts seeing some awesome photo opportunities springing up everywhere, I hope you’re seeing some!

First, let me apologize for the sporadic posting, an emergency has left me somewhat distracted. Such is life; I’m making lemonade from those lemons as we speak!

I hope everyone is enjoying the exercises we’ve been sharing. I’ve been shooting mostly film again as I develop a new way of looking at values and value control in digital photography. Today we’re going to cover a couple tips when shooting with ambient light.

Ambient light covers a lot of ground, from the living room lit only by the fireplace to the bright sunlit beaches of the Med. We’re going to focus on the darker side here to make this short.

The first and most important thing to be said about low ambient light shots is that a tripod is required! Without a tripod, you’ll never get a truly spot on level of sharpness that sets an image apart. A shot handheld with a 55mm lens at 1/30 with IS turned on will still be less sharp than a 55mm on a tripod at 1/25 with IS off. You’ll still get something you can use, and be proud of, but nothing like you’d get when you stick it the ground!

Second, consider how dark it is and how much light is available. You will need an ISO that will prove sensitive enough for your range of luminance, yet low enough to prevent excess noise to become a problem.

The third thing to consider is metering and exposure. In case you haven’t noticed, I’ve become big on using the meter to aid in getting things to levels I visualized. Your camera has a built in meter, so let’s put it to use. Do you want to use a small aperture or a faster shutter speed? To control the DOF, go to AV mode and set your desired aperture. To shoot something with more speed, go to TV and set your desired shutter speed. Before you meter, you need to decide where your want your levels to be. For a brighter image, you’ll need greater exposure in the shadows, and conversely less exposure for a darker image. Once you determine that, meter for your intended image. You’ll have a little leeway in editing, but remember that increasing your brightness in editing can introduce some seriously unsightly noise.

Another thing is your composition. You want to compose your image in a way that maximizes visual and emotional appeal. Move around to find that shot, try moving your subject. You may be able to move your light source. Zoom in or out to cover what you envisioned, and you'll notice some interesting things happen, and this ties in to our exercise on shooting only 1 focal length. Remember how you had to move around to get the shot?

Here are a couple more tips for low ambient light shooting. First, use a cable release. This will provide an even steadier platform. Second, if your camera has it, enable mirror lock-up. This locks your mirror in the up position, preventing the mirror vibrations from introducing shake into your image. A lot of cameras let you compose the image, activate the shutter button to lock the mirror, then wait for another shutter activation to actually expose the scene. Third, try to introduce balance into the composition between light and shadow. This allows you to create something that has fewer bright distractions against your main subject. Lastly, this is incredibly important, if your shooting at night or anywhere there is some risk of accident or injury, take a light and play it safe!

I know this all over simplified, but learning your gear and using these simple tips will help improve your low light and ambient light shots. It will also help you get that shot you visualized and not feel like your time was wasted.

Enjoy the week and keep on shooting.

Don’t forget to post any of your images you’d like to see here at the Hohenfels Volks Facebook page. Of course, commenting on both Facebook and here is always appreciated, too! Don't forget, we're on Google+, too!

Friday, January 27, 2012

Rice? Sand? Nope, It's Film!

Greetings, volks. Welcome to Hohenfels Volks, THE place for our place! Well, so much for no snow here in Hohenfels.

As promised last night, here’s our post on editing your digital images for the film look. We’re going to be using GIMP with some script-fu plug-ins. Even though we’re assuming you use and have GIMP there are 2 things before we begin; 1- these concepts apply to Photoshop and Paint Shop as well, but may be called something else, and 2- choose an image you think would look good as a film shot, and let’s get ready.

hohenfels Volks: Starting out, in B&W
ISO 125, f/4.5, 1/60, 53mm
We're going to start with this image. You can see the settings above. It was shot monochrome on the Canon EOS 7D, with a red filter applied and some very minor crushing of levels.

First, open GIMP. When it’s finished loading, select Open from the File menu. Navigate to your image and click Open. Once your image loads, right click on the layers palette and select Duplicate Layer. This is the layer we will be using as our background, which allows us to perform our edits without actually touching the pixels on the original image. Right click on your background and select Delete, leaving only the duplicate layer.

Right click on the duplicate layer and select New Layer. In the dialog box, Name your layer grain and select Transparency, then click OK. Make sure brush color is set for 50% gray, although darker shades will increase contrast and lighter shades will decrease it. I generally choose a darker shade to get an older style feel to the image, but the choice is up to your style and taste. Choose your Flood Fill tool, AKA Bucket Tool, and click inside the image area with your grain layer selected. You should see nothing but your selected color now. In the Mode drop down select Overlay. You can see your image now, although it will have some contrast changes.

Click on your filters menu. Select Noise, and then select Hurl. In the dialog box that appears, click the New Seed button, Then adjust your Randomization slide for about 10-15% and your repeat for 1-5. Then click OK. Your image now looks slightly contrasty and noisy, and quite unappealing. From the menu bar select Colors, then Hue-Saturation and decrease your lightness slightly and your saturation all the way down. Things are looking better, but it still needs some work. Go back to your filters menu and select Blur. From there, click Gaussian Blur. Set your radius to about 1-1.5 and click OK. The noise now looks like the grain on film, but we’re not done yet.

Next, select your background. Click on Script Fu in your menu and go to Sharpness. Select Sharper and finally click on High Pass Sharpen. Select your desired level of sharpening and click OK. You now have a new layer that is the sharpening level and looks like the lines from your original. Click the Eye Button to turn off your background.

Go back to the Colors menu and select Brightness-Contrast. I usually bring the brightness down, around 30 for most B&W photos, and increase the contrast to about 25, then click OK. Click the eye on your background layer again, turning it back on. You should be about right. The grain, contrast, and sharpness should be about what you’d expect from a general use film like ISO 200-400. If it’s too grainy, blur your noise layer in .25 pixel steps until it looks good. If your contrast is too high or low, adjust the brightness or transparency of your grain and sharpened layers.

And here's the final product. Although at this size, the grain isn't quite as prominent as it would be zoomed in, you can see the difference and the impact adding grain can have.

hohenfels Volks: finished grain in BW
This is more film like, although not quite as contrasty as pushing a little more could make it. Higher contrast can make for some nice old time photos that bring people back in time.

It isn’t perfect, but with some practice, patience, and trial and error, you can get something that looks like real film. Photoshop has plug-ins to do, as does GIMP, but the results are more natural when done manually. One important thing to remember is to make sure you remove all saturation from your grain layer. If you don’t, you’ll end up with colored noise that has no resemblance to film grain.

I hope you're working on your shots for the theme! Have a great weekend and shoot that trophy photo you've always wanted!

Don’t forget to post any of your images you’d like to see here at the Hohenfels Volks Facebook page. Of course, commenting on both Facebook and here is always appreciated, too!

Thursday, September 15, 2011

Depth of Field

Welcome back!

This time we're going to explore DEPTH OF FIELD, commonly referred to as DOF.

Have you ever noticed that some photos are extremely sharp all the way through the whole range of the image and some stop being sharp with only a small range truly sharp? This range of sharpness in a picture is DEPTH OF FIELD.

How can we control this? There are several tools at our disposal. One is controlling the distance between subjects, another is focal point (an upcoming post), but the most valuable to us, and the one we will discuss here, is our aperture or f-stop.

You might remember that aperture is the size of the "window" in the lens. You might ask, if it controls how much light gets in, how can it control the DOF?

With a narrow aperture, basically, the light becomes more tightly focused, making the DOF wider and allowing an increase in sharpness.

A couple words of caution on this:

1) This is not the cure all for poorly focused or blurry images. One negative side effect of a very small aperture, or large f-stop, is diffraction blur. The bending of light as it squeezes through the aperture causes this, and can make blur more noticeable.

2) This will require longer shutter speeds. Sometimes beyond your ability to hold a camera steady. Camera shake is really bad at long exposures!

So, if a narrow aperture will increase DOF, it makes sense that a wide aperture will decrease your DOF.

Now, it's time to break out your camera. Play with your DOF; adjust your aperture and your focus to get some images with a shallow DOF and some with more depth, or wider DOF. A great way to start is taking 2 items and placing them on your table at different distances from the camera. Shoot at the range between f4 and f16 and examine the results.

Don't you feel more artistic already? I did when I first tried it!

For more information on DEPTH OF FIELD, check out our Intro to Photography page and don't miss out on Cambridge in Colour's excellent in-depth tutorial.

That's it for this post. Here's hoping you have a great week and get some good shooting in this week-end!

And remember, if you have any questions or comments feel free to share them here or on our Facebook page.