Category Archives: Discussion

How to Remove Spots From Your Pictures

Stop Shooting Auto! is intended as a set of lessons for helping you to understand the basics of exposure, and to help you learn to use your dSLR more effectively. I’ve deliberately avoided any discussions of post-processing, because I believe that a good image is the result of solid technical fundamentals, and that post-processing should focus on minor corrections more than repairing bad shots.

Orange TulipOn the other hand, sensor dust is the bane of the dSLR photographer’s existence. No matter how thoroughly you clean your sensor, you’ll wind up with at least a few dust spots on your image if you shoot at smaller apertures. I’ve cleaned lots of sensors in my time, and while it’s easy to reduce the amount of dust on your sensor I think it’s impossible to completely eliminate it. In case you’ve missed these entries, you might want to review Why are there spots on my picture? and How To Clean Your Sensor for information on what sensor dust looks like and simple instructions for cleaning most of the dust off of your sensor.

Maybe it’s because you forgot to clean your sensor, or maybe you didn’t get all of the dust off, but eventually you’ll wind up with an image that has visible and annoying dust spots. They’ll be most visible when you have smooth gradients, like the orange tulip image that accompanies this entry. As it turns out, dust spots are fairly easy to remove. Every major image editing program should have a spot removal or spot healing tool available to you. Here are some valuable links for how to use them. Also, you want to read all the way to the end of this article, because it contains a tip that may save you from feeling like a complete idiot someday.

Adobe Lightroom spot removal brush
Photoshop Elements Spot Healing Brush
Photoshop Spot Healing Brush
GIMP’s healing tool

For all of these tools, the process is approximately the same.

  1. Select the tool.
  2. Select a brush size that’s slightly bigger than the dust spots that you want to remove– you may have to do this with trial and error, but it’s pretty easy.
  3. Scroll through your image looking for dust spots. When you find one, click it and the software should remove the dust spot and heal it using information from nearby areas of your photo. For slightly larger spots, you can paint over them with the spot healing brush.

There are other ways that you can do this, and occasionally one will work better. You can use a clone stamp, but that can be a pain in the butt. In Photoshop, I’ve recently started using content-aware fill for spots where the healing brush doesn’t quite give me the effect that I want. It’s a little bit more work than the healing brush, but sometimes the results are better. I’ve included a before-and-after photo from the orange tulip photo so that you can see how nicely spots can be removed. This one was probably a tiny little piece of lint on the sensor, judging by the shape of it.

Incidentally, these techniques work well for things other than dust spots– if you shot a portrait and the model has a zit right in the middle of his or her forehead, spot healing is a miracle drug that would put the pharmaceutical industry to shame.

There’s one thing that none of these tutorials tell you, though, and it’s an important thing. In fact, the words I’m about to write may save you a whole lot of frustration and annoyance if you remember them. Are you ready? Here we go.

Before you start removing dust from your photos, clean the dust off of your monitor! It’s such a simple thing, and yet I always find myself clicking on a dust spot over and over like a crazed monkey, wondering why it won’t go away.

DustRemoved


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I just got a digital SLR. What do I do now?

If you’ve been a very good boy or girl, Santa Claus might have left a digital SLR under the tree for you. Maybe you know nothing at all about photography, or maybe you’ve been shooting with your phone or with a point & shoot camera for a while, and now you have this fantastic new camera. What’s your next step?

A lot of photographers will give you a lot of different advice. Some will tell you that the first thing you should do is read the camera’s manual from cover to cover. Others will tell you that you absolutely have to replace the kit lens with something better. If you have exceptionally smart friends, the first thing they’ll do is send you to this website and tell you to learn about exposure. :-)

From where I sit, they’re all wrong– even the ones who sent you here. Let me explain why.

Reading the manual is great if you already have a good understanding of photography and you just want to know the specifics of the individual camera controls. Even then, it’s going to be way too much information for you to absorb all at once– it will be trying to drink out of the proverbial fire hose. Plus, the manual will tell you what all the buttons and menus and doodads and doohickeys do, but it won’t give you much of an understanding of why you’d want to do any of those things. So do read the manual, but only as much as you need so that you can turn the camera on and take some pictures. Once you get that far, stop reading and put the manual away in a safe place.

People are right that the kit lens that came with your camera probably isn’t very good. Who cares? If you’re a beginning dSLR owner, you won’t be very good either. I wasn’t. You want to see how bad I was? This is the very first image that I took with my first digital SLR.

IMG_0001_obfuscated

I think she’s the daughter of a coworker, but I’m not sure– hence the black bar on her eyes. It’s a great picture, isn’t it? Yeah, OK, not so much. The second one isn’t much better– it’s a photo of the lens cap. I kept at it, though, and a few months later when I visited Alcatraz and shot this gem:

IMG_0595

OK, at least it’s properly exposed. The focus leaves something to be desired, though. I think I was trying to capture the geometry of the tank, but I failed miserably.

The general philosophy over here at Stop Shooting Auto! world headquarters is that you should only buy new camera gear when you have a specific need that isn’t being met by your current equipment. If your lens really isn’t good enough, then by all means go invest in a better one. When you’re shooting at this level of competence, though, it’s not your equipment that’s holding you back.

As for reading this website, well… I happen to think it’s a damned fine site full of useful content, and it’s one that every beginner should get to eventually. If you just got the camera, though, you should wait a little bit before you dive in here.

So now that I’ve told you what not to do, I guess I should say something positive. The thing you should do more than anything right now is go take some pictures! The very best way to learn is to go out and practice, and experiment. You’ll get lots of really horrible photos, but that’s OK. Nobody has to see them unless you publish them on the web so the whole world can see how horrible you were when you first started out. (Ahem.)

Spend a few minutes looking at your pictures afterward. Are they good? Bad? What makes the good ones better than the bad ones? Can you identify the problems with the bad ones? You don’t have to know any technical language to do this– your eyes will understand. “This picture is too dark.” “This one is blurry.” “There’s a tree growing out of my friend’s head.” You probably won’t know how to solve these issues yet, but you’ll start to recognize common photographic problems. OK, the tree problem is easy to solve– don’t pose your friend where there’s a tree right behind his head.

After you’ve played around for a bit you’ll start to get a feel for what works and what doesn’t. That’s a good time for you to start reading. Dig into the exposure lessons here, and consult your manual when you need to know the specifics of how to do something on your particular camera. Take the time to do the exercises, since doing something is the best way to learn about it. Keep shooting, and keep experimenting, and eventually you can become a pretty decent photographer.

But for now, stop reading. Stop lusting after equipment. Just go take a bunch of pictures and see what happens.

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Holiday Gifts For The Digital SLR Owner, 2012 Edition

It’s that time of year when we all shop until our credit cards drop, then shop some more just for good measure. To get into the holiday spirit, I’ve put together a few fun gift recommendations for your favorite dSLR owner.

Happy shopping, and happy holidays!

LensBaby Spark Available for both Canon and Nikon mounts, this is a great little lens for playing around. You can tilt it or squeeze it to change the focus and get all sorts of cool focusing effects.
Crumpler 5 Million Dollar Home camera bag. I love love love my Crumpler bag! It’s the perfect thing for toting around a camera and a couple of accessories. It’s water-resistant, very well padded, and exceptionally well made. The pockets are in the right places and made for the things I want to carry. For more room (and more moolah), try the 7 Million Dollar Home instead.

If you want to go completely crazy, there’s the Brazillion Dollar Home. I want one just for the name!

Giottos Rocket Air Blaster. This is a perennial SSA! favorite. It’s useful for blowing the dust off of your gear, and for cleaning your sensor. You can also use it to blow the hair out of your face, annoy your cat, or any number of things.
DGK Color Tools Gray, Black, and White Cards.It’s always useful to have an 18% gray card in your bag, for setting white balance in difficult or unknown lighting situations. This one also comes with black and white cards as well for handling dynamic range. The set is waterproof and comes with a lanyard. At 4×5 inches, it’ll slip right into your Crumpler bag.

Gary Fong Puffer Pop-Up Flash Diffuser. Pop-up flash stinks, but most digital SLRs have one. This diffuser works surprisingly well for turning that harsh on-camera light into something softer and less obnoxious. I bought one this year when I was lending a camera to a friend, and I was surprised by how well it worked.

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What lens should I use to take a picture of the moon?

A couple of years ago I wrote How to take a picture of the moon.   It was, as you might guess, a lesson on how to take photos of the moon with your dSLR.  You may all now compliment me on my creative and clever naming scheme– I spent hours wordsmithing that one.  It’s my masterpiece.

In it I wrote “The first thing you want is the longest telephoto lens you can get, so that the moon looks like something other than a white dot. 200mm is about the shortest, 300mm is better, and 500+ is even better than that.”  That’s a true statement, but it lacks any substantiating evidence.  As you know, I’m a huge fan of experimentation and examples.  You can probably guess that a longer lens is better for shooting a far-away object, but how much better is it?

A few months ago, my friends at the absolutely fabulous equipment rental company BorrowLenses.com had a crazy sale on super telephoto lens rentals, so I did something I’ve wanted to do for a long time– I rented an obscenely large lens.  Specifically, I picked up the Sigma 800mm f/5.6 super-telephoto lens.

If you’ve never seen an 800mm lens, you should.  This beast is almost two feet long, about six inches across at the front element, and weighs in at a whopping 13 pounds.  It comes in its own well-padded metal carrying case and a sherpa to carry it, and has its own gravitational field.  OK, I made up the part about the sherpa, but it should come with one.  Maybe my trusty Gitzo tripod needs a name?

In any case, the moon.  I timed my rental so that it coincided with the next full moon.  I had an evil plan!  My plan was to steal a bunch of photons from the moon so that I could show you, dear reader, what the moon looks like when captured with various focal lengths of lens.

In order to do this, I packed the following gear:

My plan was simple: I would set up the tripod and shoot the moon with various combinations of lenses and teleconverters to show the image size of the moon with each combination.  For example, I could use the Canon lens at 200mm, and then add a 1.4X teleconverter to show what it looks like at 280mm.  Then I could do it with the 2X teleconverter to show 400mm, and finally with the two teleconverters stacked to show 560mm.  Stacking teleconverters really isn’t a good idea, since it causes your images to get all soft and cuddly, but it’s certainly OK just for demonstrating what the focal length looks like.

When you look at these images, bear in mind that they’re taken with a full-frame camera.  If you have a cropped-sensor dSLR, as most people do, imagine that at portion of the outer edge of each image has been cut off.  This Wikipedia image has a pretty good comparison of sensor sizes.  Look at the APS-C for Canon or Nikon, and that’s about how much you would cut off the edge of my images to get them to look like yours.  All of these images have a full-size version available if you’re logged into Flickr.

200mm 200mm
280mm 280mm = 200mm +1.4X teleconverter
400mm 400mm = 200mm +2X teleconverter
560mm 560mm = 200mm + 2X teleconverter + 1.4X teleconverter
800mm 800mm
1120mm 1120mm = 800mm + 1.4X teleconverter
1600mm 1600mm = 800mm + 2X teleconverter
2240mm 2240mm = 800mm + 2X teleconverter + 1.4X teleconverter

As you can see, longer lenses bring the moon in closer. Even 2240mm doesn’t quite fill the sensor on a full-frame dSLR, although about 1600mm would do so on a cropped-sensor camera.

That doesn’t tell the whole story, though– you don’t have to fill the whole frame in order to get a decent photo of the moon.  If you click through and look at the full-size image taken at 400mm, you’ll see that it has a fair bit of detail in it.  Still, when it comes to shooting the moon, longer is better.  This is one case where size really does matter.

If you decide you want to rent a long lens and try it yourself, I heartily recommend BorrowLenses.  The Sigma that I rented is pretty expensive unless you have other uses for it, but I heartily recommend the Canon 400mm f/5.6L for shooting the moon.  It’s quite reasonably priced for the focal length, and it has very good image quality.  Add a 1.4X teleconverter to it if you need additional length.  It’s also a lot easier to wrangle than the beast.

There are a couple of other things to know.  You really want to use a tripod, or something else to stabilize your camera, when you’re working with long lenses.  This will keep your images from having ugly camera shake.  The downside of this is that the moon moves pretty rapidly through the sky, so if it’s been a couple of minutes since you aimed the camera you’ll probably need to look through the viewfinder again and see if the moon is still in the frame.    Also, working with long lenses can be its own challenge.  One technique is to rest your hand on top of the lens, just above where it sits on the tripod.   This article explains it, and has a great illustration too.

Now what are you waiting for?  Go shoot the moon, and share your images with us.

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The Joys of Equipment Rental

I’m a gearhead, and always have been.  It’s an engineer thing, I guess, but photographic equipment is inherently interesting to me.   I like playing with different kinds of equipment, and experimenting with new techniques.  I also find myself wanting for specialized equipment from time to time, such as a very long telephoto lens.

A few weeks ago I decided that I was curious about tilt-shift photography.  It’s a fairly esoteric type of photography that’s used for architectural photos, landscapes, and special focusing effects.  Tilt-shift lenses are expensive, though– the cheapest Canon, the TS-E 24mm f/3.5L, runs around $1200 mail-order.  That’s a lot of money for something I probably wouldn’t use very often, and it’s way more than I’m willing to spend on my curiosity.

What’s a budget-constrained gearhead to do?

For about $50, I could rent the TS-E 24mm for a week, and I did.  None of the photos that I took with it were terribly interesting, but that wasn’t my goal.  I really just wanted to play around with it and get a better understanding of how tilt-shift photography worked.  Buying a lens for that purpose would have been cost-prohibitive, but renting was an affordable alternative.

Renting equipment is a great way to try something out before you buy it.  Do you really want that specialized macro lens, or a fisheye?  Rent it and try it out  before you plunk down a lot of cash.  Lenses are the most common things to rent, but you can also get camera bodies, lighting equipment, tripods, and more.  I discovered my favorite tripod by accident, when I rented it for a weekend.

I especially like rental for long telephoto lenses, since I don’t need one very often and they’re terribly expensive.  My next rental will be the Sigma 800mm f/5.6 super-telephoto lens.  I have it reserved for pickup next week, and I’ve timed the rental so that it occurs during the next full moon.  If all goes well, I’ll be updating “How to take a picture of the moon” with some new examples.  Wish me luck!

So maybe you want to rent equipment yourself.  How do you do it?

Most big cities will have at least one camera shop that rents equipment.  Check your local yellow pages, call around, or search the web to see what you can find.  The advantage of this is that you can often pick something up immediately.  Supporting your local camera shop is also worthwhile.  The downside is that local rentals have a tendency to be a bit on the expensive side.

Another option is one of the internet-based rental houses.  Several of them have sprung up in the last couple of years, and I’ve personally done business with a few of them.  They have their inventories online, and ship equipment to you when you rent it.  You keep the packing materials, and at the end of the rental period you repackage the gear, put the return shipping label on the package, and send it back.  Doing this takes longer than renting locally, but you often get a better selection of equipment than you can get locally, and the prices are better.

As I said, there are quite a few different internet-based rental companies.    All of the ones that I’ve done business with have been very good, but I’m particularly enamored of BorrowLenses.com.  They have an excellent selection, their prices are competitive, and I’ve gotten spectacular service from them.  Additionally, they are local to the San Francisco bay area, which is a huge advantage for me– I can order things online, then swing by their shop and pick it up, thus saving myself shipping charges.  I even enjoy their Twitter feed, which contains interesting information for photographers as well as occasional sales.

Rental is a great option for short-term needs, trying something out before buying it, or just playing around.  I highly recommend it as an alternative to buying.

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SFGate photographers’ outtakes

SFGate has some excellent photographers working for them.  While I’ve seen the occasional clunker of a photo on their pages, many of the shots are extremely good– well-seen and well-captured, and they often tell a story with few or no words required.

I just came across a couple dozen outtakes of the year from them.  Many of the photos are quite good, and some are just short of being good.  The thing I particularly enjoyed about them, though, and the reason I’m posting this here, is that each of the photos has camera and exposure information in the caption.  Several of them also have the photographer’s thoughts about why they took the shot the way they did.

Many of them were shot at high- or very-high ISOs, including one at ISO 4000.  The photographer was using a Canon 5D Mark II for the shot, which performs brilliantly at higher ISOs.  It’s also my camera of choice these days.

Study the images and think about why the photographer used the settings they did.  I think you’ll find them quite educational.

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How do I control macro (and other) depth of field?

On a Flickr discussion the other day, someone asked what the best way was to control and improve the limited depth of field when shooting with a macro lens.

Pollen In case you’re not familiar with the term, macro photography is very close-up photography.  Technically, it’s photography where the size of the image on your sensor is at least as big as real life, but most people use the term more loosely.  I’m not interested in picking technical nits here, so I won’t be picky.

If you’ve ever done any macro photography, you know that getting your whole subject in focus can be tremendously challenging.  When you’re shooting macro, your depth of field is extremely tiny, often measured in millimeters or fractions of millimeters.  Just a little bit of movement from you or your subject and everything goes to out-of-focus hell in a windblown handbasket.  Even when you have a perfectly still subject and your camera rests firmly on a tripod, shooting your subject at the wrong angle will get you in trouble.  For an extreme example, check out the larger version of the grains of pollen on the left.  The camera was at a slightly different angle than the pollen, and you can see the changes in focus at the top and bottom of the photo.  (You can also see some excellent examples of sensor dust if you look closely at the top right and bottom left corners.)

Back to our question:  how do you control depth of field when you’re shooting macro?  My response on Flickr was that you do it in exactly the same ways that you do for any other shooting:

  • choose your aperture wisely
  • manage your camera-to-subject distance
  • choose your focal point wisely
  • when you can, use depth of field preview to check your image before you shoot

We should all understand the first one by now– choose your aperture wisely.  If you’re new to Stop Shooting Auto! and you aren’t completely familiar with aperture and how it works, you should go reread this lesson and the few that follow it.  In short, choosing a wide aperture (a low-numbered f-stop like f/4) will give you a very shallow depth of field.  Choosing a narrow aperture (a high-numbered f-stop like f/16) will get you much more depth of field.

Don’t forget that there’s an online depth of field calculator that you can use.  If you click around on that site you can also find a PC version, an iPhone version, a PalmOS version, and several other tasty tidbits.

People often overlook the camera-to-subject distance when they think about depth of field, but it’s a key parameter.  Try pulling up the DOF calculator and enter the following values:

Camera format:  Canon Digital Rebel, XT, XTi, XS, XSi
Focal length: 100mm
Selected f-stop: f/11
Subject distance:  30cm

Note that 30cm is right about one foot.  Click the calculate button, and you’ll see that your depth of field goes from about 29.9cm to 30.1cm, for a total of .26cm.  That’s about two and a half millimeters, which doesn’t leave much margin for error.

Leave everything the same, but change the subject distance to 60cm.  Now, your depth of field is from 59.4cm to 60.7cm, for a total of 1.29cm. That’s still not a whole lot, but it’s almost five times what you had when you were a foot away.  Try it at more normal focusing distances, like ten feet and twenty feet, and you’ll see that even there, doubling the distance between the camera and the subject gives you about a 4x increase in your depth of field.  In short, if you’re having trouble focusing, move back.

IMG_5835Choosing your focal point can make a huge difference when you’re working with limited depth of field.  It’s often true that your camera can do a better job of focusing than you can, but it can’t choose what to focus on.  If you really care about a certain part of the image being in perfect focus, your best bet is to put the lens into manual focus mode and do it yourself.  This will give you absolute control over where you’re focusing.

In this image, letting the camera focus might well have meant that it chose to focus on a deeper part of the spadix (the sticky-outy part for non-botanists), leaving the tip out of focus.  This might have been an interesting effect, but it wasn’t what I wanted.

Don’t forget the depth of field preview button on your camera.  If you have a shot lined up, and you want to see how much of it will be in focus, press the depth of field preview button.  The viewfinder will get darker, sometimes very dark, but if you have enough light on your subject you can probably squint and get a good idea of how much of the image is in focus.

If you just can’t get enough depth of field, there are a couple of things you can do.  First, you can add more light to the subject.  I often use desk lamps for macro work, since I can aim the light wherever I want it.  Flashes are always an option, though they can be challenging to use.  If you’re outdoors, get your subject out of the shadows, or use a white reflector (even a piece of paper will work) to reflect light onto the subject.

Putting your camera on a tripod will let you use a longer exposure, and therefore a smaller aperture.  This only works for subjects that are stationary, though– don’t try it with moving objects or you’ll wind up with a blur.

And finally, if your camera is parallel to your subject it will be easier to get the image in focus.  If your subject is at an angle to the front of the lens, move the subject and/or the camera to get a better angle.  Look up at the pollen photo for an excellent example of what happens when you get this wrong.

While depth of field issues make macro photographers pull their hair out (and then photograph the strands), it’s challenging in lots of other situations as well.  Learn to control it and you’ll have a powerful tool for taking better photos.

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