Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-23-2010, 08:06 PM   #1
Veteran Member
Kguru's Avatar

Join Date: Jun 2007
Location: Perth - WestAust
Posts: 602
How cheap is this 420mm zoom?

Hi, I know it's cheap so gonna be cheap stuff, please don't berate me with you get what you pay for

Cametacamera is selling this Kenko 420-800mm zoom for about $170 + shipping, does anyone know what sort of lens build and image quality? Some samples would be great, I'm just hoping for reasonable/average quality for that money. Thanks

08-23-2010, 08:35 PM   #2
Site Supporter
boriscleto's Avatar

Join Date: Dec 2009
Location: Liverpool, NY
Photos: Gallery
Posts: 12,311
Amazon.com: Kenko 420-800mm f/8.3-16 Vari Zoom Lens, Requires a T Mount: Camera & Photo

It's basically an empty tube with some glass at either end. It has a fixed aperture. Lenses like this have been on the market forever. You can usually find them used for a lot less. Don't expect * quality results, just lots of CA & PF. It's about on par with the cheap mirror lenses available for about the same price but without the bagel bokeh.
08-23-2010, 08:38 PM   #3
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 9,148
QuoteOriginally posted by boriscleto Quote
Amazon.com: Kenko 420-800mm f/8.3-16 Vari Zoom Lens, Requires a T Mount: Camera & Photo

It's basically an empty tube with some glass at either end. It has a fixed aperture. Lenses like this have been on the market forever. You can usually find them used for a lot less. Don't expect * quality results, just lots of CA & PF.
These used to be called "girl watcher specials". If you cannot afford anything better, go right ahead. You are not out much money, and occasionally you can get a decent image out of them. Focus is difficult because of the small aperture, and as mentioned above, they are not exactly superior quality. My personal opinion is that in this price range, the reflex lenses (mirror lenses) are a much better option.
08-23-2010, 09:01 PM   #4
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,852
You'd be better served with one of the Tamron or Sigma 70-300 zooms for less cost used. IQ would be better even cropped to 400mm FOV and the lens would be much more versatile.

H2

08-23-2010, 10:21 PM   #5
Pentaxian




Join Date: Jul 2010
Location: Oregon
Photos: Albums
Posts: 1,417
A mirror lens is much easier to hand hold. My Tamron 500mm f8 is quite sharp, though contrast is not ultra high. It's also light enough to carry around just in case a long tele opportunity arises.
08-24-2010, 08:05 AM   #6
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
I have four 'long' lenses, over 300mm.

* Lil'Bigma 170-500/5-6.3, AF zoom, US$1k, 1270g.
* Spiratone 400/5.6, long tube, US$15, 770g.
* Sakar 500/8 short mirror, US$13, 420g.
* Rubinar 1000/10 mirror, US$225, 1760g.

That Kenko (also badged as Spiratone, Vivitar, others) is basically a long tube with a matched teleconverter and will have IQ equal to or worse than my bargains. You'll notice that my long tube (Spiratone) and short mirror (Sakar) were both cheap. And that's how it should be. These aren't *bad* lenses, they just aren't *good* either. In some applications that doesn't really matter, like if you're doing surveillance, blackmail, peeping, etc. A long tube has CA but decent contrast; a mirror is just the opposite; with good light, you can get decent results.

But a long tube is obtrusive and a short mirror ain't. Be careful where you use a long tube, especially if armed people are about. For real fun, put a long tube tele on macro tubes and bellows and use a shoulder-stock mount, for closeups from a distance. But that setup looks rather like an RPG launcher, so be discreet.
08-24-2010, 08:23 AM   #7
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
The one time I tried one of these hollow tube long zooms, I found in inferior in every possible way to a mirror lens - worse IQ overall, harder to handhold, bulkier to carry around 9although not heavy, since they are indeed hollow).
08-24-2010, 09:29 AM   #8
Veteran Member
Kguru's Avatar

Join Date: Jun 2007
Location: Perth - WestAust
Posts: 602
Original Poster
Thanks all so much for your advice. I will go for a mirror lens instead or an affordable Sigma "A" 400mm.

08-24-2010, 10:55 AM   #9
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,218
There are still some regular 400 manual lenses to be found on eBay at decent prices, although maybe requiring an M42 adapter.

Granted, it was like a year ago, but I won a Vivitar for under a hundred. And I've recently seen long Taks that weren't THAT ridiculously priced.

My 400 is a beast though--tripod only.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-mount, pentax lens, quality, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
My Moon shot @ 420mm Mike.P Post Your Photos! 15 04-12-2009 11:40 AM
Best cheap wide AF zoom for film? deadwolfbones Pentax SLR Lens Discussion 10 03-04-2009 08:15 PM
Cheap manual lens on cheap extension tube with cheap flash! Also cats. pasipasi Post Your Photos! 12 08-28-2008 04:43 PM
Cheap 200mm Zoom Comparison FotoPete Pentax SLR Lens Discussion 5 04-23-2007 02:21 AM



All times are GMT -7. The time now is 02:29 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top