KEH Blog


Messy Lenses and Picture Quality

Today's post is in reference to issues with lenses.

Factors that will not affect picture quality:

1. Small- medium amounts of dust inside the lens (this is extremely common and nothing to worry about).
2. Light fungus (while light amounts of fungus won't affect quality, if it's not taken care of the thing about fungus is that it keeps growing).
3. Light scratches on the glass.
4. External wear of the lens body.
5. Minor coating damage (lenses have a protective coating on the glass. Sometimes it can be damaged or etched by water marks that aren't cleaned off, salt, or other substances that haven't been removed in a timely manner).

Factors that will affect picture quality:

1. Super heavy dust (will create a haze or soft focus effect).
2. Heavy fungus (also creates a haze or soft focus effect).
3. Tons of scratches, deep scratches, chips, cracks in the glass (if you're shooting with a large depth of field, these may actually show up on your images as spots, lines, etc.).
4. Lens separation.
5. Glass elements that have fallen out of place/off track (this will prevent being able to focus properly, but is rare).
6. Major coating damage, etched glass (this usually occurs if there is extreme fungus, or if the lens hasn't been taken care of properly. Example: Soda was spilled on it and not cleaned off well).

Ways to prevent these things include first and foremost taking proper care of your equipment! Keep caps on your lenses at all times when not in use, use protective filters, keep stored properly, keep away from food, liquids, dirty environments, extreme weather conditions and humidity. If some of these issues have already started, a professional cleaning may be a good idea. For more information on how to keep your lenses clean, and how to clean, refer to our previous posts: Camera Killers: Dust & Fungus, and Keeping Things Clean.

Cleaning Grips

Sometimes the leather or rubber on the grips of lenses and camera bodies tend to turn whitish in color. This is typically from exposure to air, and nothing to worry about. It can happen on new or old equipment, and can happen on any brand. Some brands are more prone, such as older Minolta lenses. The white is hardest to clean off from a camera body because of the leather used, and easiest to clean from lens grips.

Here's our #1 tip for cleaning the white up, for aesthetic purposes only.... Take a toothbrush to it! Use a new/never used/clean toothbrush with harder bristles. Use the brush only on the grip area, and gently rub back and forth, in the direction of the grooves. The white should come right off. Now, if there's also dirt and grime on the grip, you may need to also swab a Q-tip with some cleaner such as Windex and wipe it with that as well.
above, cleaning in action

left: dirty grip with "whiting"; right: cleaned grip

And again, keep in mind that this works for most rubber grips on lenses, but not all leather grips on cameras... the camera grip whiting is much harder to get rid of, and it's usually best if you just leave that alone.

Lens Fogging

Lens fogging can occur when you switch from one fairly extreme temperature to the next. This happens even more so in humid climates. The same basic thing can happen to your camera and lenses that you've seen happen to your glasses or car windshield- a fast fog or haze created by condensation. This condensation can not only appear on the surface of the glass, but also may develop on internal parts.
The above and below images were taken with a lens that fogged-
the camera and lens were taken from an air-conditioned interior, to a very hot exterior.
To prevent this: Put your equipment in an airtight plastic bag before taking it from one environment to another. Let the equipment gradually adjust to the new temperature and then remove from the bag. Do the same thing when going back to the original environment.

Why you want to take this preventative step: 1) It won't actually save you time to skip it. If your equipment fogs, it can take a while to defog. 2) The moisture from the condensation will penetrate into your equipment. This will cause fungus to grow. If the fungus is not removed in a timely manner, the fungus can etch the glass which will ruin the clarity of you shots for as long as you use that lens. Fungus may be difficult for the untrained eye to detect, and is sometimes costly to clean. The condensation can also cause rust and internal problems in your camera which will affect its functioning.


Lens Separation

What is "lens sep"? It's when two cemented elements begin to separate.

What does it look like? Like a patch of oil when the sunlight hits it. There will be an iridescent rainbow colored area, usually along the edges. The shape varies, but it's typically crescent or wave-like.

What does it affect? Due to the reflection is causes, it can increase flare and reduce contrast.

Can it be repaired? It is usually not cost effective to have it repaired. It is fairly labor intensive and expensive to fix.

How does it happen? Lens separation typically happens in older lenses. It can be caused by the breakdown of the cement or glue over time. Not storing lenses properly and leaving them in very hot conditions can contribute to the break down. Once the sep has started, it will continue to worsen over time. Sep can also occur in prisms.

Anything else? All lenses that come in to KEH and have "sep" are automatically graded as UG. Also, the coloration in sep should not be confused with an overall rainbow-ish reflection on a front element of a lens. Some lenses (again, mostly older) have a coating that can appear rainbow when moved in the light. If it's even and covers the entire lens, it probably isn't sep. If it's a visible patch on a part of the lens, then it probably is sep.

Digital Lens Compatibility Part 1

We're bringing you information on lens compatibility in three parts, starting with understanding the two basic types of digital SLR sensor sizes and the appropriate lenses to use.

You either have a full frame sensor, or a digital sensor that is smaller in size referred to as a APS-C (Advanced Photo System type-C). Typically, the higher-end pro cameras have the full frame sensor and the mid-range to lower end digital SLRs have the APS-C sensor. Depending on which type of camera you own determines which types of lenses will work on your camera body.

Sensor size comparison chart

Canon: Their APS-C type lens mount is called EF-S. The lenses that are specifically designed for these cameras will be marked with EF-S on the lens, and have a small white square near the mount. Canons film lenses are EF, and have the typical red dot near the mount.
Canon digital SLR mount with mounting spots for EF-S and EF lenses
Canon EF-S lens mount (white dot)
Canon EF lens (red dot)

With Canon, both EF-S lenses and EF lenses will work on the APS-C cameras. On the full frame and film cameras, only the EF lenses will work (EF-S lenses won't even mount onto a full frame or film body). Canon manual focus lens mounts are not interchangeable between AF and digital either.

Nikon: Distinguishes its digital APS-C lenses with DX. All Nikon lenses (both DX and non-DX) will physically fit onto any other Nikon mount including both digital sizes and 35mm film.

Even though Nikon's APS-C lenses will mount onto film bodies, they will not cover the full image size. This can cause vignetting or soft focus around the edges of the image, especially at the widest of the lens zoom range.

Because of the design of the sensor of a digital camera, there are more light rays reflecting back through the lens than 35mm lenses. Digital-only lenses (or APS-C designated lenses) have specially designed coatings to absorb stray light and preserve image contrast and are also typically lighter in weight.

If you're using a full frame/film lens on a APS-C camera, another thing to keep in mind is that the focal length and crop factor changes. A 35mm lens that is mounted to a full frame camera will provide a slightly wide-angle view, while when mounted to an APS-C camera will provide a slightly telephoto view. (You can read more about crop factor here, or stay tuned for more info. and example photos on Friday).

Other APS-C lens designations:
* Pentax DA
* Sony DT
* Sigma DC
* Tamron Di II
* Tokina DX

Stay tuned for parts 2 and 3!


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