ARTICLE 10–TELEPHOTO LENSES
Article 10- TELEPHOTO LENSES
Prepared by Ottawa/Kanata photographer, Jeff Ryan/Ryan Studio Of Photography
Being a visually oriented individual from the earliest years of my profession, I was introduced to varying optical qualities of lenses represented by various production companies. Photographers were for the most part years back, carrying a number of telephoto lenses with them to achieve specific variances in image creation. One of the many reasons a person would elect to acquire several telephoto lenses was due to the fact that they not only rendered the subject matter differently, but the background areas were also affected. Depending upon which lens you acquire, you will notice that there is a tendency of the longer lenses to flatten perspective which can enhance the subject matter. The limited concept of thought regarding selecting a lens to bring objects in closer was addressed a considerably long period of time ago, and great discussions permeated at social events regarding this questionable reasoning. Photographers must have a definitive objective when purchasing specific lenses to represent their artistic vision.
At one point in my working career, I was employed in a photography retail outlet, and this afforded me the luxury of conducting extensive testing procedures on numerous telephoto lenses. I became very well versed in the visual acutance characteristics of several optics which benefited me when conversing with the public. A client on one occasion, entered the store with obvious apprehension regarding the discussion of telephoto lenses due to his limited knowledge of their operation. He indicated that he could not fully grasp the concept of what exactly a telephoto lens was. How would it differ in comparison to the standard lens that was affixed to his camera as a product of permanence that many people’s thoughts subscribed to? At this point, I determined that the most efficient way of describing to someone of respectful, limited understanding of the product, was to provide comparisons between binoculars to camera lenses. Describing at length how a binoculars fixed focal lens operates by indicating that the only way to bring objects closer to you when looking through binoculars, is quite literally to walk towards the object itself. Binoculars, unlike zoom lenses, have stationery optics that are quite specific in themselves. This method of comparison equated to simplified comprehension for an individual with limited exposure to a product. For photographers decidedly preferring fixed focal length telephoto lenses over zooms; they have been superbly refined to excellent quality standards and there should be no hesitancy on behalf of the buyer regarding indecision when making a purchase.
Certain telephoto lenses have been designed for specific applications and I could provide the reader with several examples of comparison, however I will address one item in particular that I acquired years ago worthy of discussion. The endless conversations of acceptable quantities of diffusion in photography were elaborated on extensively by novices, professional photographers and lens manufacturing companies in the 1970’s & 1980’s. During this time frame, the Mamiya Corporation elected to produce a sophisticated product-(The Mamiya 150mm Soft Focus Lens), that would provide photographers with the ability to alter the visual density of diffusion by inserting aperture discs into the lens itself. The discs appearance were circular with excessive holes punched in the plastic discs themselves, and basically the way this lens operated was as follows: depending upon the quantity of diffusion required for the scene or portrait you were creating, you would select one of three diffusion discs and insert that disc into the rear element of the lens. Again, the discs varied visually meaning, discs either had many holes punched in them or fewer holes to alter the effect of diffusion visually. This lens was quite unique at it’s time of production because it was capable of separating/detaching, the front half of the lens with the rear portion. Once the lens was separated, it provided the user the ability to insert or retract the disc in the lens providing remarkable levels of creativity to the user. On another note, should the user elect to use no discs at all, the lens became an excellent sharp focus portrait lens in itself. In addition, should the user leave a disc of any diffusion in the lens it would not be recorded when aperture settings of F8 or smaller were utilized.
Telephoto lenses do not suffer from the deficiency of “lens slippage problems” that I mentioned previously regarding the characteristics of zoom lenses. This zoom condition usually occurs over time or excessive usage of the product. They (telephotos), should still be considered as valid items in ones arsenal of equipment that most photographers have at their disposal. Many professional portrait studios still operate with preferred telephoto focal length portrait lenses over zooms. Generally speaking, telephoto lenses of the 150-180mm length are excellent choices for head and shoulder imagery or ¾ length representations of an individual. A visit to a retail camera store, or by going on line to view the diversified, exorbitant selection of telephoto lenses will enhance ones knowledge greatly pertaining to these products. I currently own a 150 and 250mm telephoto lens for varying applications. In the studio I commonly select the 150 however when outdoors, the 250mm is an ideal choice because it allows one the benefit of still being within the proximity of the person being photographed, making communications possible, and also narrows the overall viewing area making the subject take precedence over the scene.
A Brief Digression Regarding Lens Features:
Continuing our discussion of the above, there are additional points of interest I would like to provide the reader with in this featured column. Firstly, lenses as you have noticed feature several working apertures or often called f-stop openings on them. There are obvious reasons why lenses contain these however I would like to indicate that the majority of optics from a technical point of view, operate best at apertures set approximately 2-3 stops down from maximum aperture. Service technicians and lens designers have commented and agreed upon this fact for a number of years. For example: perhaps you have a 100mm F2.8 macro lens for close up photography. Two to three stops down from maximum aperture would appear as the following: F4, F5.6, F8. This lens would operate at peak efficiency if positioned within the proximity of the F8 setting. It will produce the best sharpness and contrast in this area as opposed to being set at F2.8 or F22 for instance. This rule is consistent with the majority of lenses on the market and while you are making photographs, you might want to place your exposures within this vicinity unless you are going to require imagery with minimum or maximum depth of field characteristics.
Price of lens includes warranty:
As interesting as it may seem, several novice/advanced amateur photographers in Canada are still unaware of the fact that when purchasing a new piece of camera equipment, they are at the same time paying for the warranty for one full year from the date of sale. Several Canadian camera enthusiasts I know of, have compared the Canadian and U.S. market selling prices for years now always indicating how high the prices are continually inflated to in Canada. What they fail to realize is that should your piece of photographic equipment require servicing during the first years time, all labour, shipping costs, parts, insurance costs are included when you purchase your new gear, hence the higher costs. This is one of the reasons why you might feel like your being taken advantage of initially, but with labour rates being higher in Canada and the general cost of doing business always on the increase accompanied with the difference in currency exchange rates, it’s easy to comprehend the up front expenses that may seem staggering and unjustifiable for many.
Speed of Lenses:
For the purpose of this example, I will be making reference to zoom lenses, specifically the 80-200mm F4-(normal speed lens), and the 80-200mm F2.8-(high speed) lens.-(Many lenses of varying focal length could be made reference to for discussion purposes incidentally). Perhaps you have heard photographers mention over the years they were glad they purchased a “fast lens” as opposed to a “slow lens” for their photography. Fast lenses are more often than not, more expensive than slower ones due largely to the higher quality glass materials used in the manufacturing of these lenses and overall barrel/lens construction. What they are referring to when they indicate “fast” is as follows. If you are making a series of photographs during the day, and at one point you notice your exposure settings (particularly your shutter speed) becoming increasingly longer in duration as you continue your picture making due to decreasing light values; your camera now informs you the light levels are becoming very low and that you are risking underexposure if you continue at your current exposure settings. If you are photographing at an aperture of F4 which is already the widest opening possible on your lens, the only way to continue producing film imagery under these low light levels is to decrease your shutter speed which slows the cameras movements down giving the film more time to see the light and therefore correctly expose it. (Digital users have the option of altering the ISO setting in the camera to compensate for variances in light conditions). However, if your hand holding your camera at a very slow shutter speed at present, setting it to a speed slower than what it is currently set at would result in blurred photographs because of your in-ability to hold the camera steady for such a long period of time. If you had a fast lens there would be a good chance, depending on how low the light levels actually are, that you could continue hand holding your camera and still continue the picture making process with appreciable results. For this example we could say that your indicated shutter speed is 1/60 second at F4. What options you now have available to you are the following. Either change your aperture settings to F2.8-(when using the fast lens, which now gives you one extra full stop of light entering the lens and exposure chamber) and leaving your shutter speed of 1/60 remaining the same. Or, when using the slow lens, change your shutter speed to 1/30 second while keeping your aperture at F4 which might cause you now to blur the photograph. A well thought out photographer has to ask themselves what type of photography they create most often when making lens purchases. If you find over the years that you are going to be producing extensive existing light image creation under various light levels, one inexpensive way of preventing underexposure problems, is to purchase higher speed films which naturally respond to light levels faster than slower speed products. Higher speed film will most likely provide you the luxury of preventing underexposure problems however, films that are of a higher speed have debatable drawbacks/characteristics to them; particularly increased grain structure. Once again, digital users would simply have to alter the ISO setting and most likely continue the image making process without these limitations. Grain structure for film photographers has improved significantly over the years minimizing the previously unwanted granularity, now producing photographs with phenomenal degrees of sharpness. On another note, several photographers of commercial portrait application have intentionally purchased exceptionally high speed films with noticeable, pronounced grain structure to enhance the soft appeal of their imagery. Excessive grain accompanied with varying degrees of diffusion can produce striking portraiture reminiscent of yesteryear and should be considered.
With Good Wishes,
Jeff Ryan Photography/Ryan Studio Ottawa, Ontario. 2017
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