Thursday, August 2, 2018

Tamron 500mm f/8 tele macro mirror lens



Tamron SP 500mm f/8 tele macro mirror lens (model 55b)

A lot of photographers just don't like mirror lenses at all but personally, I think that they're a great way to get into long lens photography on a tight budget, even though the results from mirror lenses can be a bit hit and miss. I definitely think that it's because of their lack of consistency and ability to produce acceptable images 100% (or even most) of the time that mirror lenses are much more suited to digital photography than they were ever suited to film photography, ie no wasted time and wasted money on films/processing etc. and no 10 days waiting time for a wallet full of 36 blurry prints. Getting sharp pictures with mirror lenses can at times be extremely difficult due to a number of reasons, camera shake, fixed aperture, extremely shallow depth of field (especially on subjects close to the camera), and very low contrast images due to insufficient light, Oh! and dough-nuts (often by the dozen), but taking into consideration the limitations of mirror lenses and given the right conditions most of the better quality reflex mirror lenses are capable of producing sharp images.
The Tamron 500mm f/8 is described as a Tele-Macro but using this lens for macro work is very difficult as it's depth of field is minuscule and focusing on small insects from 6ft away and getting the image sharp is extremely difficult but for some larger insects like dragonflies reasonable results can be had if the photographer is patient and more selective especially with composition. When using this lens as a macro for insects I've had some success using the following method, I always try to get the subject square on and flat to the plane of the camera's lens/sensor and also bear in mind that the flatter your subject is the sharper your final image will be. So think flat, square on, well lit and bang in the middle of the lens, and don't go for fancy angles and compositions when shooting insects or wildlife if absolute sharpness is your intention as the focus and depth of field fall off considerably when the subject is at an angle to or leading away from the camera/lens. Selecting and focusing square on upon one single isolated subject out on its own is much better than trying to capture a small group of objects or subjects bunched closely together, simply because mirror lenses have such weird bokeh, anything surrounding, in front of, or slightly behind the main subject won't have a gentle out of focus blur about it and it won't be sharp either, unless the main subject or subjects are some considerable distance away from the camera and the distance between the target and near background objects are more compressed. Mirror lenses work well when photographing relatively close or midrange subjects that are set against a plain background (sky or distant landscape) as this lessens the visual confusion in the final image.



Tamron SP 55B 500mm Mirror Lens

The build quality of this lens is very good and due to its design it's also ultra lightweight and portable especially when considering that this is a 500mm lens, focusing is super smooth and it's comfortable to hold. The lens is easy to use but sharpness and exacting focus are as much dependent upon the eye and patience of the user as working within the limitations and parameters of mirror lenses in general. Two models of the 500mm lens were produced, the earlier 55B (shown above) and a later model 55BB. The earlier model came fitted with a tripod lens collar as standard and the optional accessories included a set of four 30.5mm filters, 3 coloured filters for Black & White photography plus one ND filter. Additionally, a clear glass 30.5 'Normal' filter was incorporated and factory fitted as standard to the rear of the lens. It's important to note that at least one filter should always be in place when taking pics (usually the clear normal filter), I believe these rear filters are intended to correct the refracted light path as it leaves the lens and before reaching the film/sensor.
If the original 'Normal' filter becomes lost then I suppose an ordinary 30.5 clear UV filter might be a suitable alternative replacement.  An 82mm thread on the front of the lens accepts the screw-in lens hood which in turn is also threaded to take 82mm filters intended for conventional use. After the lens's mirror was slightly modified in 1983 the tripod lens collar was discontinued and the lens model number was changed to 55BB. The filter set was also supposedly discontinued but I've seen many secondhand models of the 55BB which include a full 30.5 filter set. The owner manuals for both the 55B and the later 55BB are virtually identical (apart from the front covers and a reference to mounting the lens on a tripod), and on page 13 both manuals state that a 30.5 rear filter should always remain in place when taking photographs.


Page 13 from owners manual model 55B


          Four Spotted Chaser Dragonfly


Dragonfly, Four Spotted Chaser, taken with a Tamron SP 500mm f/8 Tele Macro Mirror lens

Mirror lenses tend to have lower contrast than regular lenses so bright sunlight, fast shutter speeds, ISO's higher than 500 and a monopod are basic requirements for good sharp images. Apart from the basics, bumping up some of the in-camera settings such as contrast, sharpness (to highest) and clarity also helps a lot with this lens.



      Fallow Deer eating reeds


Fallow Deer eating reeds, taken with a Tamron SP 500mm f/8 Tele Macro Mirror lens




      Clock tower


         
 Clock Tower,  500mm Tamron Mirror Lens, Slight sharpening applied and angle/perspective corrected


           Blackbird


Juvenile Blackbird (trying to cool down? in the 2018 UK heatwave)
Bokeh

Backgrounds produced by mirror lenses aren't always peppered with doughnut rings (the result of out of focus highlights caused
by the obstruction in the centre of the lens) although backgrounds are quite often a bit woozy and confusing due to a fixed aperture and the peculiarities of mirror lenses in general. The image of the bird above was taken at a distance of about 10 -13 feet and with just about enough DOF to separate the main subject from the background.


Thankfully due to their natural characteristics, quirks and peculiarities mirror lenses can be used creatively and some cool and unique dream-like effects can be achieved but nothing is easy and in the case of effects, subject selection and composition is critical.



          


Tamron SP 500mm F/8 Mirror lens  (Model 55B)

Specifications

Focal length................. 500mm

Aperture...................... F/8 (fixed)
Construction................7 elements in 4 groups
Angle of View.............. 5'
Coating........................ BBar multilayer coating
Min. Focus.................. 1.7 metres (66.9")
Max. Magnification.... 1 : 3  (2 x Tc 1 : 1.5)
Length......................... 87mm
Diameter..................... 84mm
Weight ........................ 576 g (20.2 ounces)
Lens Hood .................. Detachable, screw in (82mm thread)
Filter rear.................... 30.5mm 'Normal filter' supplied/fitted
Filter front................... 82mm thread
Optional Accessories .. Rear filter set Nd4X, Y52, O56, R60
                                           Flat field 2x tele available.

                                                                 (BBar = Broad Band Anti Reflection)