The first post is from an Olympus white paper. No kidding wiki isn't a white paper. Hybrid lens design means exactly that. Parts of different tech. So including telecentric design elements with standard lens is still using telecentrics.
On Mar 26, 2015 5:10 AM, "karl shah-jenner" <shahjen@xxxxxxxxxxxx> wrote:
Randy, the article you linked states:
"Telecentric optical path means that light hitting the sensor is traveling closer to perpendicular to the sensor, resulting in brighter corners, and improved off-center resolution, particularly on wide angle lenses"
on a fact basis, this is a fail they've found a good technical word and they're abusing it, telecentric optical path means nothing like what they describe - they are merely highlighting the benefits of a long flange to film distance and pretending it's something that it's not. They could just as easily have used the word (incorrectly) in the 70's and 80's when they switched from mirror-up designed wide angles to the more modern designs. All they did was push the lens out further from the film with the use of appropriate lens elements.
It's closer to the perpendicular to the film as well, but it's still convergent/divergent. Only when it's a lens system can it be parallel, and only when it IS parallel is it parallel.
White papers (From Wikipedia again: "A white paper is an authoritative report or guide issued either by a government, or by a company in business-to-business marketing,.. presenting the issuing body's philosophy on the matter... a tool for persuading customers .. considered 'grey literature..") are not often tech documents, and I've seen my fair share of tech documents which have as much marketing as any sales brochure.
For those confused by reading all this, PLEASE go look at the images produced by a telecentric system- you'll be quite amazed at the sort of things such lenses can do. ""Because light is collimated as it enters the lens, images of identical objects are imaged with the same magnification, even if they are at different distances from the lens" .. that's pretty cool..
Lens designs have jumped ahead from time to time for various reasons. Sure there were SLR's pre 60's, but on the whole they had limited lens lineups as the majority of lens makers were still manufacturing their own old lines with camera makers either designing their light tight boxes to fit the lenses, or putting the lenses in appropriate barrels for the focal lengths. Subsequently wide angles were often set very close to the film plane and came with light fall off issues, but they did the job and produced unworldly images unfamiliar to the general public. In the 70's camera makers got in on the lens game big time with whole 'systems' springing up - as much for the barbie style collectors as for any cameraman. This time saw some seriously interesting developments in lenses such as pushing the wide angles further out, zoom lenses became more common (especially in the 80's), and with increased affluence came escalating sales - good times. Problem was as with software companies, accountants get used to ever increasing sales and they needed to get their buyers to buy not just once but again and again and again, and good rugged old reliable cameras became a liability. It's not all rampant capitalism though, developments brought some genuinely beneficial products to we consumers. 1990's- Enter the boon of autofocus- once the sneered at as the bastion of point and shoot cameras, it along with auto metering appeared big time in SLRs, pro and high end cameras and this is where the serious consumer churn began - initially old lens designs were reconstituted for the new lineups, but due to their weight these were rapidly replaced with newer designs optimized for autofocus - light weight components were the priority and this steered lenses into the area of light weight plastics, which saw developments in asphreric designs undreamed of before. This produced some truly outstanding lenses (and some naff ones too). Then we saw the rise of digital, this time whole systems were dumped, replaced, dumped again and it brought benefits and drawbacks.. but mostly it brought SALES. but now we had the big boys playing in the sandpit.. Electronics companies stepped into the ring and stomped flat more than a few players, and along with their wealth, r&d skills, they brought their marketing clout and best of all, willingness to outsource to better qualified parties. Lens makers once again found themselves making lenses. Zeiss and Schneider were on more cameras than they've been in forever - and there are new players to the game too.
For me one of the best examples of new designs , a real eye opener - the Korean Samyang 8mm fish eye. I'd coveted a fish eye lens but wasn't happy with any I saw until I stumbled across this little beauty http://www.kenrockwell.com/tech/8mm-f35.htm - lenses like these are a truly great advance for photographers with an eye for what they're seeing.
Across all these years we've seen many shrill claims and barrow loads of sales hype, but as the technical involvement of consumers has fallen, buyers know less and less about the products. from autofocus to image processing algorithms.. even those with technical backgrounds or loads of enthusiasm find it harder and harder to understand all the technologies going into these increasingly miniaturized circuits - and often even the professionals in their respective fields became further removed from the creative process (software writers use software they don't understand to write software, computers design computers to parameters given to them)
I had one tech put it to me: When the secretaries had their typewriters replaced with PCs they were sent off on week long training course, when the techs who repaired the typewriters were given PCs to fix they were expected to just know how to do it.. they were technicians
k
