How cheap is this 420mm zoom?

Kguru · 08-23-2010, 08:06 PM

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

**boriscleto** · 08-23-2010, 08:35 PM

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.

**Canada_Rockies** · 08-23-2010, 08:38 PM

Originally posted by boriscleto

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.

**pacerr** · 08-23-2010, 09:01 PM

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

civiletti · 08-23-2010, 10:21 PM

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.

RioRico · 08-24-2010, 08:05 AM

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.

Marc Sabatella · 08-24-2010, 08:23 AM

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).

Kguru · 08-24-2010, 09:29 AM

Thanks all so much for your advice. I will go for a mirror lens instead or an affordable Sigma "A" 400mm.

Ira · 08-24-2010, 10:55 AM

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.

08-23-2010, 08:06 PM	#1
Kguru Veteran Member 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

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08-23-2010, 08:35 PM	#2
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	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
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	Originally posted by boriscleto 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
pacerr Loyal Site Supporter Join Date: Jan 2008 Location: Paris, TN Photos: Gallery \| Albums Posts: 3,350	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
civiletti Pentaxian Join Date: Jul 2010 Location: Oregon Photos: Albums Posts: 1,435	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
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	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
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	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
Kguru Veteran Member 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: 5,216	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.