Tamron SP 500mm f8 Reflex lens, a review of Mirror lenses
Tarmon SP 500mm F8 Mirror Lens, Real world review
When you make a start in the world of Photography, Sooner or later you will want to own a dedicated Long Telephoto lens. These lenses offer the ability to get some great images in the world of (Landscape, Wildlife, Portrait and Sports) Photography.
Fixed focus (None Zoom) Telephoto lenses come in many focus lengths, but the most usable are 200mm to 600mm, depending on how much magnification of distant subjects and objects you need. The cost of these lenses my surprise many starting photography and to be honest even many long term photographers, they can start in price range from around €800 and end up way into the many €1000’s.
There is however an alternative option with this type of lens, this being to look at what are called Reflex or Mirror Lenses. These kind of lenses replace some of the glass elements within their construction with two Mirrors both used to fold the light entering the front glass element in much the same way as a reflex telescope does.
i.e. NASA uses this method in the Hubble space telescope that has produced some amazing ground braking images of the cosmos.
Third party and OEM Camera manufactures started making these lenses in the 1970’s and continued through to the 1990’s, today mostly only third party lenses are available. The quality of these Early OEM/Third party – mirror lenses was very high, even second hand some of these lenses can set you back some €300 to €800 on ebay, even today in 2017.
I purchased a Reflex lens made by Tamron (500mm SP F8) way back in 1988 and in this post I just wanted to share my thoughts on some of its upsides and some of its downsides.
To be honest, I have not used this lens very much, for two main reasons.
Firstly : at 500mm and with an lens aperture of F8 it needs to be Tripod or at the very least mono pod mounted in order to create very sharp images. This maybe a little unfair as this is true for most long lenses but Nikon VR lenses are so good at helping go handheld!
Secondly : these lenses have one very different down side to that of refactor (Glass only) lenses, they produce a doughnut ring effect on bright out of focus objects or even just areas in the image that have a bright, lighting than the darker areas around them. I have included some examples at the bottom of the posts images below.
With the first point above, today in 2017 with the high ISO abilities of SLR cameras such as the Nikon D7200 and D750, this issue has been made redundant to a great extent! When this Tamron lens was produced, 35mm film could only produce clean images at a rating of no more than ISO 400.
Today the Nikon D7200 can work very well between ISO 3200 and 6400 with very little help from good noise cleaning software in post processing, this up-rates the usable shutter speeds for hand held work for even a lens of 500mm at f8, letting you work handheld more than ever before !
Remembering that even on a DX sensor slr, you need for some 750mm (X 1.5 DX factor!) to keep a shutter speed of 1/800th to 1/1000th to create fully stable images, If you have a steady hand. Even on a cloudy day ISO 1600 gives a shutter speed of around 1/1600th and ISO 1600 on a D7200 is little to worry about! noise wise. It is for this reason that I am starting thinking of trying using this lens again.
For the rest of this post and review of the lens, I will let the following images do the talking, with a small amount of comments made in each of the related image types.
Tarmon SP 500mm F8 Mirror Lens – sharpness and quality
To test for the image sharpness and quality I placed the camera on a tripod, I don’t use a remote release, so there could be some small effects but all in all these are sharp images.
You can see from the below image that this lens can produce some very sharp images under the correct conditions, its just as good as some much more expensive glass only lenses from Nikon.
I have no worries here and would be very happy in trusting this lens to produce sharp images from corner to corner of the frame.
Above : Nikon D7200 with Tamron SP 500mm Mirror lens, Tripod Mounted
As image sharpness has been tested above, what about color fringing and other detects, color fringing is visible in an image at bright edges in the frame, so I used the wires and other equipment on the telegraph post in this image, I see no fringing Green, blue or otherwise in this image.
So again I would trust this lens to produce sharp and clean images that need little or no post processing to clean them up later.
Using the lens – in the Landscape
The following images speak for themselves, just general landscapes and animal images from medium focus distance subject to long distance landscapes, the town and wind farm in the last landscape is some 8km away from the location of taking the image, crazy!. Again its sharp enough taking into account the haze of the atmosphere, no color fringing problems in the wind turbines.
With the main set of images here, I am less happy with the out of focus effects as the bokeh of this lens is not great!, anything bright and a little out of focus (i.e. The grass!) takes on a distracted look, feeling tangled and distracting with the image smoothness, Most noticeable in the two images of the sheep sitting down.
Those Doughnuts !! OMG!
As you can see from the photo of this lens sitting in my camera bag at the top of the post, a mirror lens is constructed very much like a reflecting telescope, like this diagram :
You can see that the center of the front glass element is used to hold the housing for the smaller secondary mirror in the construction, that folds the image light back down the lens and into the camera.
This system works amazingly well but for one problem!
For in-focus areas of an image the central lens obstruction is never visible, however for brighter areas of an image that are out of focus this central obstruction created by the secondary mirror housing, created a bright doughnut effect.
In the below images this is very clear!
The light gaps in the trees below turn into bright cycles, the rain on the table in the background focus also does the same.
In some images you can work around this effect and even use it as an interesting advantage?, you just have to get to know when this kind of lens is and is not usable !!!
For the most when you have a subject that has the potential to create this circle effect ! it just distracting and not likeable. This is the point at which the little price you paid to get a budget Telephoto lens €300 not €2000 starts to gets you back !!!
Getting Arty , MayBe?
Like any camera lens, Mirror lenses have their down sides (Slow, bright Cirles, Manual focus, etc …), you just have to get to know these features and ether use them to your advantage or don’t !!!
Some people love the bright rings and make good use of them 🙂 , one use could be nighttime street photography ?
So then ?
So if your looking for a cheep way to get a telephoto lens into your camera bag, a Mirror lens is well worth looking at in my own opinion. Don’t expect to work quickly with them or be lazy in your approach, however – but then most telephoto lenses need hard work to get good images, with a mirror lens you just have to add a little on top!
In the end, just like with all of your image making, you get out what you put in !!!!
Will I take this lens out more than I have? Maybe ! most likely not !! Watch this space ?
If I was starting again with few lenses and wanted a low budget long lens, would I get a Mirror lens , Hell YES !!! , With Great high ISO SLR’s even more so !!!
Sometimes the harder you have to work to get good images , the more you learn !!!!
Also see : Mirror Lenses – how good? Tamron 500/8 SP vs Canon 500/4.5L, a older review, ISO has moved a long way since this article but its a great comparison test (€300 Tamron v €2000+ Canon).