Comments on: D131f700 Refractive Lens For Astronomical Telescope http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/ Finding The Best Telescope Lenses Fri, 20 Jan 2012 10:49:37 -0600 http://wordpress.org/?v=2.9.2 hourly 1 By: kazimitz http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2572 kazimitz Fri, 09 Apr 2010 23:25:06 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2572 OK, I'm curious. How is a non-stabilised version better? OK, I’m curious. How is a non-stabilised version better?

]]> By: lig moba http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2566 lig moba Fri, 09 Apr 2010 19:53:05 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2566 InquisitionNews: said: Mystery Object Defies Astronomical Classification | Wired Science | Wired.com InquisitionNews: said: Mystery Object Defies Astronomical Classification | Wired Science | Wired.com

]]> By: gomaee klust http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2425 gomaee klust Tue, 06 Apr 2010 14:34:00 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2425 Permeability and permittivity are magnetic and electrical properties of a material (they are also properties of free space). There is no way to calculate them from any more fundamental properties. Call Permeability mu, permittivity epsilon. The speed of light is 1/sqrt(epsilon*mu) as derived from Maxwell's equations Permeability and permittivity are magnetic and electrical properties of a material (they are also properties of free space). There is no way to calculate them from any more fundamental properties.

Call Permeability mu, permittivity epsilon.

The speed of light is 1/sqrt(epsilon*mu) as derived from Maxwell's equations

]]> By: schone tempkins http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2385 schone tempkins Mon, 05 Apr 2010 12:54:44 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2385 National Microscope Exchange is now selling the newly released ATAGO RX-5000 digital benchtop refractometer for testing fruit juices, soft drinks and other products requiring brix or refractive index readings. National Microscope Exchange is now selling the newly released ATAGO RX-5000 digital benchtop refractometer for testing fruit juices, soft drinks and other products requiring brix or refractive index readings.

]]> By: siegan magant http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2343 siegan magant Sun, 04 Apr 2010 09:24:11 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2343 How come in this video you talk about large magnifications, but in the other vids, with the same scope your advice for magnification is smaller. Did I miss a link? Or a trick? How come in this video you talk about large magnifications, but in the other vids, with the same scope your advice for magnification is smaller. Did I miss a link? Or a trick?

]]> By: benganucci http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2297 benganucci Sat, 03 Apr 2010 03:34:13 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2297 The lens is fine, Canon have a balancing act to perform, though - they want to supply a lens to a 'beginner/hobbyist' camera to get people to buy them - but they have to do it economically. The same goes for all manufacturers. At the same time, they can't give you a lens that is no good. Anyway, that doesn't answer your question. Photojournalists have a habit of carrying two bodies with a lens on each(and a couple of flashes etc). An increasing number of modern day journo's have a wide/normal zoom and a telephoto zoom. Your kit lens and a 70-200mm are good ranges. The difference between your lens(es) and photojournalists is the speed of them. They run larger maximum apertures. And there's the rub. Cost. You'd be paying $1300 for a Canon 24-70 f/2.8 and $1300-$1800 for a Canon 70-200 f/2.8 without or with Image Stabilization to get the speed they require. Sigma and Tamron will offer cheaper alternatives, of course. You could ramp up the ISO on your camera to keep your shutter speeds high enough with your kit lens and the other lens you choose (and get away with it) but I doubt you can get away with only one body - things happen too fast for you to be able to change lenses at a moment's notice. The flashguns are pretty much essential, too. If, by beginning photojournalist, you mean 'bit of a hobby because I see a load of celebs' then you're good to go. If, however, you're being paid to get results then you should consider ways of raising the capital to get a higher grade pair of bodies and faster lenses. The lens is fine, Canon have a balancing act to perform, though – they want to supply a lens to a 'beginner/hobbyist' camera to get people to buy them – but they have to do it economically. The same goes for all manufacturers.

At the same time, they can't give you a lens that is no good. Anyway, that doesn't answer your question.

Photojournalists have a habit of carrying two bodies with a lens on each(and a couple of flashes etc). An increasing number of modern day journo's have a wide/normal zoom and a telephoto zoom. Your kit lens and a 70-200mm are good ranges. The difference between your lens(es) and photojournalists is the speed of them.
They run larger maximum apertures. And there's the rub. Cost.
You'd be paying $1300 for a Canon 24-70 f/2.8 and $1300-$1800 for a Canon 70-200 f/2.8 without or with Image Stabilization to get the speed they require. Sigma and Tamron will offer cheaper alternatives, of course.

You could ramp up the ISO on your camera to keep your shutter speeds high enough with your kit lens and the other lens you choose (and get away with it) but I doubt you can get away with only one body – things happen too fast for you to be able to change lenses at a moment's notice. The flashguns are pretty much essential, too.

If, by beginning photojournalist, you mean 'bit of a hobby because I see a load of celebs' then you're good to go. If, however, you're being paid to get results then you should consider ways of raising the capital to get a higher grade pair of bodies and faster lenses.

]]> By: fowlands sarik http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2266 fowlands sarik Fri, 02 Apr 2010 07:45:01 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2266 Cameras with wide angle lens (28mm) are increasingly popular, now there are even ultra wide angle (25mm) cameras available. Pansonic has lead the way with wide angle lens on so many of their models. I have a 28mm lens and it allows me to take pictures that I couldn't otherwise. Here is a good description. http://panasonic.net/avc/lumix/popup/wide_angle/index.html Cameras with wide angle lens (28mm) are increasingly popular, now there are even ultra wide angle (25mm) cameras available.

Pansonic has lead the way with wide angle lens on so many of their models.

I have a 28mm lens and it allows me to take pictures that I couldn't otherwise.

Here is a good description.

http://panasonic.net/avc/lumix/popup/wide_angle/index.html

]]> By: fazius http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2165 fazius Tue, 30 Mar 2010 03:17:50 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2165 If poss, could you also get bottle of gin from duty Free - I will reimburse you. Price of alcohol here <b>astronomical</b>. If poss, could you also get bottle of gin from duty Free – I will reimburse you. Price of alcohol here astronomical.

]]> By: valam http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2155 valam Mon, 29 Mar 2010 19:22:33 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2155 -- they're more sensitive. -- they give instantaneous results. -- they don't require darkroom processing. -- they allow the operators to sit inside, where it's warm. (big plus.) -- image stabilization software can be used to correct for movement. – they're more sensitive.
– they give instantaneous results.
– they don't require darkroom processing.
– they allow the operators to sit inside, where it's warm. (big plus.)
– image stabilization software can be used to correct for movement.

]]> By: sket http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/comment-page-2/#comment-2120 sket Sun, 28 Mar 2010 17:46:48 +0000 http://www.telescopelens.org/d131f700-refractive-lens-for-astronomical-telescope/#comment-2120 tags: birds, mystery bird, bird ID quiz [Mystery bird] photographed near the Serengeti National Park, Tanzania, Africa. [I will identify this bird for you in 48 hours] Image: Dan Logen, 18 January 2010 [larger view]. Nikon D300, 600 mm VR lens with 1.4 extender. ISO 400, 1/1600 sec, f/6.3. Exposure compensation -1.3. Please name at least one field mark that supports your identification. Read the rest of this post... | Read the comments on this post... Also check out the featured ScienceBlog of the week: Obesity Panacea tags: birds, mystery bird, bird ID quiz

[Mystery bird] photographed near the Serengeti National Park, Tanzania, Africa. [I will identify this bird for you in 48 hours]

Image: Dan Logen, 18 January 2010 [larger view].

Nikon D300, 600 mm VR lens with 1.4 extender. ISO 400, 1/1600 sec, f/6.3. Exposure compensation -1.3.

Please name at least one field mark that supports your identification.

Read the rest of this post… | Read the comments on this post…
Also check out the featured ScienceBlog of the week: Obesity Panacea

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