Ask David: Aperture Changes, Focus Lock, Stealing Photos and Curtain Flashes :: Digital Photo Secrets

Ask David: Aperture Changes, Focus Lock, Stealing Photos and Curtain Flashes

by David Peterson 0 comments

In my regular Ask David column, I answer common questions from my readers. By answering them here, I hope to help everyone else who might have this problem, and not just the person who asked the question.

Today, we cover aperture changes, the focus lock button, stealing photos, and curtain flashes.


First up today, Amy Vallance, from St. Johns, USA asks

I was reading about aperture & depth of field but on my camera (Sony Cyber-Shot DSC-H7) I don't have F22 or anything higher than F8.0. Is there a conversion or is there something I need to buy?

Unfortunately, you're suck with the aperture values on your lens. The DSC-H7 is not a SLR camera, and you can't change lenses to switch the built-in lens for one with a higher (or lower) aperture range.

However, you can simulate using a higher or lower aperture value. By getting closer to your subject, more of the image to be out of focus when using a low F number. Likewise, by focussing on an object further away, you can increase the range of what is in focus for higher F numbers. I explain fully how to do this in my Depth of Field Secrets course.

Jean Blyth from Prescott, Arizona wants to know if she can increase the aperture of her camera.

Since my camera (Nikon Coolpix 8800 only has an aperture to f8 and I take landscapes, should I take it at a lower ISO equivalency to take a slower capture? I ask this in relation to your last class about aperture priority.

No, a slower shutter speed won't change the aperture of the image. If your lens only goes to F8, you're stuck with that. However, as I explained above, you can get more of your image in focus by focussing on the horizon. So you can still get perfect landsacpes with the F8 aperture.

I still recommend using a low ISO when taking landscapes, as it will improve the colors in your photo.

Linda Buttrey from Shelburne, Canada asks

Re: Free tip #6 (auto focus then switch to manual focus).  I have a Nikon D90 and it has a focus lock button. I have difficulty understanding the manual about this button.  Does it do the same thing as auto focussing, then switching to manual focus?

Yes, the Focus Lock button on your D90 (and most other cameras) does a similar thing than switching to manual focus, however it also locks the exposure. The button can also be called the AE-L/AF-L button. Locking exposure means the camera will use the same light settings for all your photos, rather than taking a new brightness reading for each separate shot.

The best time to use the Focus Lock button is when you want to take multiple shots with the same exposure and focus. For example, if you are taking shots to be used as a panorama, or want to take a few shots in quick succession with the camera pointing in slightly different directions.

The process is:

  • Half-depress the shutter as I explain in the Two-Step shutter process
  • While still half-pressing the shutter, press and hold down the Focus Lock button. Keep holding the Focus Lock
  • Change the camera's position if you need to to compose the shot the way you want to
  • Fully press the shutter button to take the shot. Release the shutter button but keep holding down Focus Lock
  • The camera keeps the same focus and exposure settings while you keep Focus Lock pressed
  • Take a few other shots by fully pressing and releasing the shutter button
  • To release the focus lock, just let go of the Focus Lock button.

Eliztia Stols wants to know about people stealing her photos.

I went on google to create a website for myself to sell my photos, its a free website, so i wanted to watewrmark my photos so that the people wont steal my photos. The guy told me it wont help to water mark my photos because some of the poeple copy the photos any way, so I wanted to change it so that they cant left right click then the guy told me some of the people can boycot that aswell, so how can i protect my photos, and sell them?

Yes, almost every method of copy protection can be circumvented. If your computer can view the photo, it can be stolen.

However, there are ways to make it not worth time to steal it because of the amount of work needed to remove a watermark from an image. Here's how I do it. I'll also outline another method next week. Stay tuned!

Finally, Des Crocker, from Australia wants to know more about Curtains.

More of a technical query than quality type. When, how and where soes one choes between 1st and 2nd curtain?

Hi Des,

Canon's Website.

I hope that helps.

If YOU have a question, please feel free to send in your question on my Ask David page. Because of the amount of questions I receive, I can't always answer your specific question, but I do try!

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