Over the years I have like many of you had questions on why I get low quality photographs that seem washed out, out of focus or just plain not usable. I put together a few examples of what causes a lot of the pictures you take to be tossed into the electronic trash bin.
Lets start with longer lenses - 300mm and greater. Longer lenses pose a more challenges to master repeatable tack sharp photos. Shooting across open areas with the added weight hand holding even with VR / IBIS turned on you sometimes wind up with poor quality images.
One term Astronomers say is: May you have "clear skies
". Clear Skys does not necessarily mean no clouds it also refers to the air quality - stable air. Astronomers and photographers have something in common - AIR Quality, I am speaking about turbulence
caused by rising air currents which can cause light to refract. Everyone has on a warm day experienced looking down a long road and see what appears to be the illusion of water, or rising air. This is caused by the surface area being heated by the sun's rays causing the cooler air at the surface to heat and rise. The image to the left is a great example that no optics in the world can achieve good images when shooting across open space where the heat wave phenomena is occurring and it becomes more apparent with longer lenses due to focal compression.
Along with the heat, your photographs may be impacted by air pollution or even tree pollen, or even fine mist which can degrade image sharpness -
How to avoid bad air - If you need to be in an area shooting at a certain time of day, there may not be much you can do. If you have choices, the earlier the better before the sun rises too high in the horizon. Cooler days are generally better, attempt to get as close to the subject as possible, If at all possible avoid shooting across open areas. Generally speaking, this issue occurs more in the summer months.
There are two general statements to explain here and apply equally to all lenses and cameras. One is somewhat common the other not as much. The more common issue is referred to as back or near/front focus errors the camera and lens combo may have. You buy a new highly rated lens and you put it on your camera and go out for a day of fun shooting. When you return and process the images one after the other are not exactly sharp - trying it again you see the same results. So, it must be the lens right? not necessarily. The distance the camera thinks the lens is focused can be off by a few millimeters, either in the front or back of the actual focus point on your subject. Most people forget about checking for this, there are tools and techniques on the internet to adjust and improve lens focus accuracy. Nikon D500 and D850 have a built-in menu item that allows you to dial your lens in and save the settings for that lens. You can tell if your camera/lens combo has this issue by looking carefully at your images - do you see sharpness beyond or in the front of the subject? If so, then you may be suffering from this issue.
Speaking of Back Focus Front Focus. Link to lens - camera calibration
Focus is very close
It may be best to leave good enough alone. Nikon calibration does not support half increment adjustments. So, close enough may be all u can get.
There can be other reasons that cause focus issues, like some debris on those focus sensors that sit below the viewfinder. But yet there is one other possibility - your focus point is off..thats right. Where you think the focus point is might not be where the camera thinks it is. Here is an example of the issue and you can clearly see in the photograph the red focus box is off to the right of the subject, and no it was not me. There is not much you can do about this but ask the camera manufacturer to repair/adjust/calibrate it. In my opinion, if your camera suffers from a focus point error, it is well worth the cost to send it in and have the adjustment completed - save you lots of frustration. You can tell if your camera has this issue by carefully taking a photograph using the single focus point, and noting where your point and subject is, then open Lightroom and use the menu to show the focus point.
Mechanical or vibration & Stabilization issues:
I bought a converter for my tripod head and when I made the conversion it increased the vibration going into the lens - like a tuning fork. Once I converted it back my blurry photos disappeared. A link to that article.
Vibration Reduction / Stabilization issues can be tricky to track down and when and how you should use VR. Lots of people I know simply turn VR on and forget about it. I spent a month testing using VR on my 600mm and while on a tripod VR off made the images better. In many situations, I found that when VR was off and the package was mounted on a very steady tripod - I got sharper images with VR off - like a Gitzo Series 4. Using a lighter tripod like a Gitzo series 3 - when VR was off I got more blurry images - due to the fact the weight of the lens and camera on a lighter tripod had some shake/vibration to it.
Sometimes you don't have a choice - you get what comes along. I like birds, so if the opportunity presents itself I take a photo. In these mid-day harsh shadow situations, you can expect a challenge dealing with the bright to dark areas - especially with your dark feathered friend such as this such as this fine looking fellow. This image illustrates the loss of fidelity due to the lighting, although the lens and camera did a great job of holding up to the wide dynamic range. In post-processing, it is possible you can pull out the dark shadows but that can be challenging and time-consuming.
Technique: It is true, I get sloppy sometimes and depend on the camera and lens to save my bacon. There is a lot to be said about understanding good photography techniques. Do your homework and study how Lighting, setting the camera for front or rear curtain during flash shooting, ISO settings, F-stop, shutter speed all can make or break the photograph. This is a huge area most of us take for granted and rely heavily on the camera to take care of it for us, like going into one of the auto modes and forgetting to check your shutter speed as your light changes.
They say you get what you pay for and I believe that to be true in most situations. Canon, Nikon, Sigma, Tamron, Fuji, Sony, to name a few manufactures all to make excellent camera lenses. I personally never had a lemon - what I have received was the poor quality lens from less known third-party sellers in my early days trying to save a few dollars. Over time older glass may start to show its age if they are mounted on a high-resolution camera sensor. A good example is my fantastic Nikon 16mm f/2.8 I owned for 20 years, but year after year as high-resolution digital sensors hit the market - the lens could not resolve past about 20mp. It is still a great fun lens, but limitations in the optic design 20 years ago in the era of emulsion - is a big difference now. In short,
In summary - I found over years of photography most sharpness issues were due to the reasons stated above and not necessarily the lens. Happy shooting and Clear Skies.