# What is Fast Glass and why do I need it?



## Bob Hubbard (Nov 7, 2010)

*What is &#8220;Fast Glass&#8221; and why do I need it?*




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What is &#8220;Fast Glass&#8221; and why do I need it?
- Bob Hubbard*

 Read enough discussions about photography and you&#8217;ll eventually hear the term &#8220;Fast Glass&#8221;. But what is it?

 Read the list of numbers on your lens and you&#8217;ll see something like  F4-5.6. To many beginner photographers, this is confusing. What does the  F4-5.6 mean?  This is a rating indicating how wide you can set your  camera&#8217;s aperture while shooting.  A wider aperture allows for more  light reaching the camera&#8217;s sensor or film in a shorter time.  The wider  you go, the faster the light pours in, just like the wider the hole in a  boat, the faster the water fills it. What does this mean for the  photographer? A wider aperture, ie: faster glass, means that you can use  a faster shutter setting, allowing you to better freeze motion and  capture the action.

 The challenge for most sports photographers is that while most venues  are well lit for the average person, they tend to be dimly lit by your  camera&#8217;s eye. Most consumer lenses allow for an aperture of about F3.5  at widest. This would mean setting your shutter speed to 1/30th-1/60th  of a second to get a good exposure. Unfortunately, at this speed you run  into the combined issues of hand shake and motion blur, resulting in a  lot of &#8216;eh&#8217; shots, even with today&#8217;s vibration reduction capabilities.  You can of course use flash to add more light, but some places frown on  that, and most on-camera flashes are too low powered to do much in  bigger venues, or cause red eye, harsh shadows and under exposed  backgrounds.

 The solution is to look for lenses that allow you to shoot with a  wider aperture, or faster. Modern camera lenses are complex sandwiches  of different lenses made up of different types of glass and coatings.  This complicated system lets modern lenses to offer excellent image  quality and light sensitivity, allowing the photographer to capture a  quality image. However, these lenses can cost some real money.

 Serious sports shooters tend to shoot with fast zooms in the 70-200mm  F2.8 or better range, however these lenses are outside the budgets of  most casual shooters as they cost thousands of dollars. For a hobbyist  on a tight budget, look for the 50mm 1.8 lens. Both Nikon and Canon sell  an inexpensive version of this for about $100US. Because it is fixed at  50mm, you can&#8217;t zoom it like you can your kit lens, and will have to  physically get closer or farther from your subject. But, it will allow  you to shoot in low light situations without flash and capture good  images.

 So, remember, fast glass means lenses that can allow more light in  faster, allowing for better images in low light situations.  They also  tend to be better built and a higher quality lens than lower prices  consumer lenses, allowing for better clarity and sharper colors in your  images.

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Bob Hubbard is a professional photographer specializing in martial arts    event, nature and portrait photography. He is also the CEO of   SilverStar  WebDesigns Inc, a web design company  specializing in   martial arts sites, as well as an administrator on the  popular martial   arts communities MartialTalk.com, Kenpotalk.com and  FMATalk.com. His   martial arts photography can be found there as well as  at his martial   arts photography web site, martialphotos.com. He may be  reached through   these sites.

Copyright © 2010 &#8211; Bob Hubbard &#8211; All Rights Reserved
Permission is granted to reprint this article on websites, blogs and    ezines provided all text, links and authors bio is left intact.


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## Bill Mattocks (Nov 7, 2010)

Fast glass is often the correct answer to this perpetual problem.  But it is not the only way to address this issue.

Consider that the problem is based on the never-ending dance of obtaining enough light.  Here are the constraints.

1) If you use a slower shutter speed, your subjects will be blurred by their motion.  This is true of photographing martial arts, dancing, and many indoor sports.  Generally, we do not want motion blur in the photos.

2) If we use a faster shutter speed, we do not get enough light to properly expose the scene.  As stated above, the photos are 'too dark'.

Solutions:

1) Flash.  Obviously this is not something that you want to use for many forms of indoor events, as it is distracting.  And even if you use flash, you must be close; flash does not travel very far.  Ever go to a football stadium and see all the flashes from people's cameras as they try to take photos of the football players from up in the stands?  Trust me, it's not working.  Their flash doesn't go anywhere near that far.

2) Faster ISO.  This is the 'speed' of the film or digital sensor.  With regard to film, this is printed on the box, with regard to digital cameras, this is either selected automatically by your camera or it is manually controlled by a menu setting.  In many cases, people have the option to control ISO manually, but often they don't know it or they don't pay attention to it.  The trade-offs here are that higher ISO numbers often mean grainier images.  Newer digital cameras have very good high-ISO sensors these days compared to older digital cameras.  A good reason to consider a newer camera if this is an issue for you.

3) Faster glass.  This is what Bob mentioned.  A faster lens has a wider aperture opening, so it lets in more light.  The downside to a faster lens is that a) it costs more and b) there is a narrower 'DOF' (Depth of Field) that can result in very blurred images if your focus is not spot-on.  This type of blur is not due to subject motion, but due to the focus from front-to-back of the scene.  In any given scene, a higher aperture number (smaller hole) results in deeper focus; a lower aperture number (larger hole) results in a shallower focus.  This can be an advantage at times; notice photos of athletes that you see in the newspaper - typically the person in focus is in sharp focus, while the background is totally blurred out.  You might want this, but beware that you need to be very careful about your actual focus; DOF won't 'cover' any focusing errors you or your camera make.

I agree with Bob's assessment.  I also use a cheap manual-focus 50mm f/1.7 lens when I shoot martial arts.  It allows me to avoid using flash or grainy high-ISO sensor settings, and still keep a high enough shutter speed to freeze the subject motion.  However, focus is a real pain; I miss lots of shots due to not getting the focus dead-on the subject.

In the end, it's always a series of compromises when shooting under these conditions.  The ideal solution would involve a very fast sensor / film that would not suffer from image degradation (noise or grain), but the technology is not quite there yet.  It will come, though; when it does, this age-old problem will be neatly resolved.


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## zDom (Nov 8, 2010)

Sports guys here at the paper have been telling me the the latest digitals can shoot insanely high ISOs before getting grainy

(actually, with digitals it is, technically, called "noise" but I think most of us prefer to describe it as grainy as an homage to the film days)


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## Bob Hubbard (Nov 8, 2010)

My problem with upping the iso is the images just seem softer as you go up, and have less detail. I can post process the noise down, but it never seems as sharp as when I shoot at iso 100-200 with the faster glass.  But, it is a lot cheaper to bump the iso up to 800-1600 than to buy an f/1.2 lens.


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## Carol (Nov 11, 2010)

Bill Mattocks said:


> 1) Flash.  Obviously this is not something that you want to use for many forms of indoor events, as it is distracting.  And even if you use flash, you must be close; flash does not travel very far.  Ever go to a football stadium and see all the flashes from people's cameras as they try to take photos of the football players from up in the stands?  Trust me, it's not working.  Their flash doesn't go anywhere near that far.



And many times the flash will work against you.  What I've been learning from wandering around at night with my camera is that with auto settings, if the flash is set to fire, the camera may compensate by changing the f-stop, ISO, and/or speed to compensate for an environment that is brighter than it actually is.


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## Bill Mattocks (Nov 11, 2010)

Carol said:


> And many times the flash will work against you.  What I've been learning from wandering around at night with my camera is that with auto settings, if the flash is set to fire, the camera may compensate by changing the f-stop, ISO, and/or speed to compensate for an environment that is brighter than it actually is.



Well...I should have mentioned that I don't always let my camera control those things.  As often as it makes sense to me, I shoot manual, so it won't change those things.


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## Carol (Nov 11, 2010)

Bill Mattocks said:


> Well...I should have mentioned that I don't always let my camera control those things.  As often as it makes sense to me, I shoot manual, so it won't change those things.



Oh...I totally understand that you do a lot of manual (and it looks fabulous!)   You would already know to not fire the flash   I'm just speaking more in general terms.  

Some advice you gave me earlier is advice that I am taking to heart (digital is cheap -- shoot lots).  I have been able to grok a lot more by taking multiple shots (different settings) of the same settings and then comparing them.  The computer is still smarter than I am in many environments, but I'm starting to catch up.


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## Bill Mattocks (Nov 11, 2010)

Carol said:


> Oh...I totally understand that you do a lot of manual (and it looks fabulous!)   You would already know to not fire the flash   I'm just speaking more in general terms.
> 
> Some advice you gave me earlier is advice that I am taking to heart (digital is cheap -- shoot lots).  I have been able to grok a lot more by taking multiple shots (different settings) of the same settings and then comparing them.  The computer is still smarter than I am in many environments, but I'm starting to catch up.



You have a very good eye, and I have no doubt you're headed for great things. :asian:


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