Part 4: Camera & Lens Considerations with the ALZO Macro Tabletop
Close-Up Lenses and Manual Focus
A camera setup with the ALZO Macro Tabletop involves a number of variables including: type of camera, focal length of lens or zoom settings, close-up capabilities and exposure/white balance setting capabilities. If you are using a camera with interchangeable lenses, then a true macro lens is ideal.
If not, a fixed focal length lens or zoom lens with a close-up setting built-in might be adequate. Beyond that, close-up lenses (similar to threaded screw-in filters) can be used on lenses to gain focusing closer than the closest focus setting on the lens. These close-up lenses are primarily made for the front of interchangeable lenses with a set of front threads ranging from 49mm to 67mm. Any thread size outside of that range can sometimes utilize thread adapters to either go up or down in thread sizes to match.
The other option is extension tubes, which allows the lens to focus closer than the closest setting on the lens. The tubes go between the lens and the camera body. Most tubes do not allow for auto-focus, but for our purposes, the lens should be manually focused in most cases. Not only do we recommend using manual focus, but also manual white balance and manual exposure settings as well. Most cameras have those settings, even smaller fixed-lens point and shoot types of cameras. Some point and shoot cameras may be limited in capabilities, but can still be utilized for this type of photography. If you lack manual exposure settings, auto or program can be used along with the exposure adjustment setting (+/-) to adjust for too light or too dark an auto exposure.
Auto-focus and Shadowing
Auto-focus can focus adequately as well given that subject matter we are probably dealing with is somewhat flat and does not require a tremendous depth of field (focus area from closest sharp focus to furthest sharp focus.) Please turn off any built-in flash and let the camera use the ALZO 100 Cool Lites to give the proper lighting. Auto white balance can be fooled. The best option is to set the color balance to the correct type of light you are using and in the case of the ALZO 100 Cool Lites, that would be the “Daylight” setting. When using your lens setup, whether it’s with a macro lens, macro settings, close-up lenses or extension tubes, try to use the longest focal length or zoom setting you have that will still show the entire subject. That will help to minimize lens distortion and give you most working distance you can get. Most wide angle lenses or wider zoom settings tend to have more distortion than the longer settings, so use the longest ones you can, even if that requires raising the camera to the highest point on the column. The other issue using a longer setting or focal length lens helps eliminate is shadowing on the subject from the lens itself. If the lens is too close to the subject, depending on how the lights are positioned, shadows created from the lights striking the lens itself may cause a shadow to fall on your subject. By getting the lens further away from the subject, that becomes less of an issue. If the camera and lens cannot be raised to avoid shadowing, then possibly the lights can be lowered to allow the shadow from the lens to fall outside of the subject area. Once the camera and lens is close to an ideal height, a zoom lens or zoom setting can fine tune the image area covered so the subject can fill the frame as fully as possible. A fixed focal length lens would need a bit more column adjustment fine tuning to achieve the same result. Make sure to fill the camera frame as much as possible with the image of the subject without cropping your subject. That will give you better image quality than having a lot of space around your subject that needs to be cropped out later, meaning that the image will have to be enlarged to match what could have been accomplished filling the image frame from the start. When you need to enlarge the image, you can lose quality.
If using the ALZO 14″ Light Tent, note that the lowest the column may be is about 2/3rds the full height before striking the top of the tent. At that point, the ALZO Ball Head would most likely be needed to position the camera directly over the center of the baseboard. If using the column near full height, the extension should not be required. Another consideration is how to trigger the camera. With the camera suspended on the column and focused as close as it is, any camera shake at all will certainly be visible in the image. If you can remotely trigger the camera, that is ideal. The best solution is triggering without any wires that might transmit vibration to the camera as you are holding the triggering device.
If it has a cable, the best bet is to let the camera settle for a few seconds and then fire the camera without moving the cable at all. If you have no remote device at all, then use the self-timer setting, set to at least 5, if not ten seconds. That will give the camera vibrations (resulting after you push the button to start the self-timer) time to settle down before firing. We also need to address the actual use of the camera on the ALZO Macro Tabletop as far as viewing position. Since most cameras have a standard viewfinder or screen that is fixed to the back of the camera, it may be awkward to see either one if the baseboard is placed on a high table or counter top. If the camera has an articulated screen that can be re-positioned at an angle to see better, that makes it easier. Otherwise, the baseboard can be placed on a lower surface or even on the floor if necessary for easier viewing.