7D Does filter size affect quality of the lens?

I

iFilm7

Active member
Does filter size affect quality of the lens?
im thinking of buying the kitlens for the 7D 18-135mm IS... it has a filter size of 67mm
and the "better" lenses have filter sizes of 72mm/77mm
does it really affect the quality of the resulting picture?
im thinking bigger the lens the better...?
 
Quality of the lens has nothing to do with filter size. What you are paying for, is the little F number. The lower (numerically) that number is, the more light it lets in. The more light it lets in, the better the camera will perform in lower light conditions and the cleaner your footage will be. The filter size is just a by-product of this.

A lens that is 5.6 lets in half as much light as one that is F4. A lens that is 2.8 lets in twice as much light as one that is F4, and 4 times as much as one that is 5.6.

Zooms in the SLR world generally run from 2.8 (best) out to variable aperature lenses at 3.5-5.6. You don't want those. Select a lens that has a constant maximum aperture. They cost more but are WELL worth it. Good lenses lose very little value over time because demand for them remains high. We have 7D users who are using manual focus Nikon lenses over 30 years old. And they look GREAT.

You'll curse your slow (small filter size / higher F-Stop number) lenses time and again in challenging scenarios. I've NEVER heard anyone complain about their F1.8 or F1.4 glass. It's a joy, it's easier to focus, and it holds it's value.
 
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In theory yes. Faster glass is better because it's larger, uses better materials, is built better, is generally sharper, and it aimed at pros. The average Joe is not going to spend $400 on a lens for his $500 camera. But a pro who's shooting with a $6k camera is going to look at that lens a very different way.

Think of it this way. For every 1 F-Stop faster your lens is, that is half the light you don't have to use to light your scene. You'll spend less on lights, you'll need less power, you'll have less to carry, and you crew will thank you endlessly. The actors won't have to bake under a bunch of hot lights either. It's a huge win for everyone.
 
iFilm7 said:
so in theory/reality a 67mm will produce less satisfying results than a 72mm/77mm lens?
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This is not the way to think about it. Filter size might have correlations but thats it. Its not an absolute and there are plenty of other metrics you could use as well.
 
Ohh okay I get it now! (:
btw should i still get the kit lens with the 18-135mm and buy a 50mm lens?
What are your suggestions?
 
iFilm7 said:
so in theory/reality a 67mm will produce less satisfying results than a 72mm/77mm lens?
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No, it comes down to taste and what your purpose is. A 17mm will distort facial features while a 72mm will render a more pleasing closeup. Then again perhaps your intention is to distort features for comedic effect.

Another thing to consider if you're shooting wide open at a F1.4 is that your DOF will be very thin and you'll have a devil of a time focusing. A lot of lenses that open to F1.4 are typically soft wide open so you'll often find yourself stopping down for the sharpness and increased DOF to focus. I think it's kind of overrated to shoot wide open, I'd be looking at lenses that open to a 2.8 and instead of trying to shoot in darkness actually buy some china balls or cool lights.
 
iFilm7 said:
Ohh okay I get it now! (:
btw should i still get the kit lens with the 18-135mm and buy a 50mm lens?
What are your suggestions?
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I'd leave that kit lens alone, and buy some decent glass if you can afford it. If things are a bit too expensive for you (and let's face it, times are tough for a lot of folks right now), then you can get by with the kit lens until you can do better.
 
Isaac_Brody said:
Another thing to consider if you're shooting wide open at a F1.4 is that your DOF will be very thin and you'll have a devil of a time focusing. A lot of lenses that open to F1.4 are typically soft wide open so you'll often find yourself stopping down for the sharpness and increased DOF to focus. I think it's kind of overrated to shoot wide open, I'd be looking at lenses that open to a 2.8 and instead of trying to shoot in darkness actually buy some china balls or cool lights.
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Isaac brings up a good point here. One which deserves a bit of discussion as it is often a problem.

A lens that opens to 1.4 will have very shallow DOF if you shoot it there. Shooting wide open therefore becomes a choice that needs to be weighed. If you look at what is arguably the best series of film lenses on the planet, the Arri Master Primes, you'll note that they are all T1.4. This is very similar to F1.4. Their next cheaper set of lenses (if you can call a $150k set of lenses cheaper) is the Arri Ultra Primes. And these are all T1.8. Other manufacturers offer lenses in T2.0 (like the Cookes S4 lenses) or even T2.8 (like the Cooke Panchros). Each corrosponding set of lenses is cheaper. It doesn't mean they are not quality lenses. I am sure the Cooke Pancrho 50mm is still $5k or so and would probably shame most of the glass we put on our cameras.

Isaac also points out that a lot of glass that opens to F1.4 is soft at that size. And he's right. Which is why the F1.4 glass that is really sharp costs much more and is so sought after. Also important to this discussion is to realize that the further you get away from 50mm in each direction, the harder and more expensive it is to make sharp glass in large aperatures. A 50mm F1.4 lens may cost you $200. A 35mm F1.4 lens may cost $500, and a 24mm F1.4 lens may cost you $2000 (and will have a filter size around 72mm). A 200mm F1.4 would cost more than my car, while an 85mm F1.4 lens would be around $500.

Isaac points out that it is somewhat overrated to shoot wide open. Again I agree in most instances. However, if you are shooting with something like the kit lens, you'll be wide open a lot since your maximum aperature will be around F4 a lot of the time of not less. And these lenses are not anywhere NEAR as sharp wide open as a good 1.4 would be closed down to the same aperture. And then there are those times, when you'll be trying to fly under the radar. Maybe shooting a crowd scene at twilight or daybreak. And you just can't drag a set of large lights out on the city street. The faster lenses are worth their weight in gold when you are trying to be discreet. The same goes for those trying to shoot at dark wedding receptions. Do you try to dictate to the bride that she needs more lights, or do you put on a piece of fast glass, stop down to F2, and have 4 times as much light as you would if you had the kit lens on? It's a choice.

As a former pro photographer, I have a fondness for very fast glass. I know what kind of advantage it can bring. It can extend the shooting day. It can make shots that are impossible with an F2.8, entirely possible. It can allow you to get shots in places where others fail (especially with documentary footage), it can allow you to shoot in sensitive places where you can't take lights like a library, or historical building.

Having fast glass is having choices. Having slow glass is having to make excuses or workarounds when things get a bit tricky. You pay more for them. But believe me, one day, you'll learn why.

I have vowed to myself that I will not buy any glass for my 7D slower than F2. That's my choice. I will need to break that to get my 20mm (35mm equivalent). So be it. The 14mm Nikon 2.8D (equivalent to a 22mm on the 7D) is $1800. I won't be getting that lens any time soon. I hope I'll be buying it on someone else's dime!


Best of luck with your choices.
 
iFilm7 said:
Yeah I dont have much to spend on better lenses.
but after seeing this footage [shot on 7D 18-135mm] then i mean thats just awesome...
http://www.youtube.com/watch?v=bKg1_QoRPv4
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Notice that nearly every bit of it was outdoors in bright sun. If that's your plan, slow lenses will work. I just bought a film camera. Two lenses were offered with it. A Nikon 28-80 F3.5-5.6 and a Sigma 70-300 F4-5.6. I offered $40 a lens and my offer was accepted. The lenses don't have a scuff on them and are in like new condition. They will become loaners for me.

My first 3 pieces of glass will be these:

Basic wide

http://cgi.ebay.com/Nikon-24mm-f-2-...iewItemQQptZCamera_Lenses?hash=item51910bc0df


Basic 2-shot

http://cgi.ebay.com/Nikon-35-mm-f2-...iewItemQQptZCamera_Lenses?hash=item3cab010907


Basic 1-shot

http://cgi.ebay.com/Nikon-Nikkor-50...iewItemQQptZCamera_Lenses?hash=item4a9f43e92d


I've have the 2 slow zooms so I can cover 28-300 outdoors if I really need to. Or indoors if I don't mind really pushing in a lot of light.
 
Yeah ... such clips makes you wonder what you can really do with any piece of glass (and good sun shining, CA?) ;) Someone was saying anyway that since we want to do video with these DSLR then we could get away with cheaper glasses compared with people who want to get stills. This clip confirms that.
Of course the outstanding info from Perrone holds on :)

PS
Perrone, are you having a long night ? In EU we are waking up but in Florida must be deep night or ... VERY early morning ;)
 
It's 1:30AM here. Pretty typical night for me. I was at work until nearly 11pm tonight working on a podcast project. Came home, late dinner, now fooling around reading about slow lenses. :)


Funny and true story. When I was evaluating this new film camera and these slow zoom lenses, I set the camera up on a tripod and attached one of the lenses. I taped a chart to the wall 10ft away. I lit the chart with 1kw of light at 8ft. With the lenses zoomed all the way in and reading F5.6, both had trouble locking on with autofocus. All my cursing and bad memories of slow lenses and missing shots suddenly came pouring back.

I will never miss another payday because I was too cheap to buy fast glass. It's false economy. And there is a reason that nearly every piece of cinema glass is F2.0 (T2) or faster. Even with lighting budgets in the millions of dollars, fast glass is still highly sought after among professional cinematographers.
 
Err, I've never had any AF trouble with any of my newer "slow" lenses in anything other than super low light. I mean low enough that even f/1.4 wouldn't cut it for exposure.

Yes, there are situation where slow zoom just don't cut it but there are also situations where they are better than a fast zoom in terms of size and weight.
 
iFilm7 said:
Is this a fast lense?
will it do good indoors and [obviously] outdoors?
but its like $900+
http://www.the-digital-picture.com/Reviews/Canon-EF-24-105mm-f-4-L-IS-USM-Lens-Review.aspx

-.-'
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Yes, it's an excellent lens.

If you noticed, all the lens I linked to are manual focus. Buying AutoFocus lenses costs more, and for movie purposes, you don't use auto focus. So personally, I see no reason to pay extra for it.

They do add some benefit in other ways, but not enough for me to think about paying double for them.
 
shaocaholica said:
Err, I've never had any AF trouble with any of my newer "slow" lenses in anything other than super low light. I mean low enough that even f/1.4 wouldn't cut it for exposure.

Yes, there are situation where slow zoom just don't cut it but there are also situations where they are better than a fast zoom in terms of size and weight.
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Note that I said I was working with a film camera. It's many years old and it's autofocus isn't as good as the new DSLRs.
 
I would recommend shooting within your means now and learning more about the craft. You could buy all the best glass - and some do - without knowing what they are paying for.

Start shooting, have fun, and grow in your skill before worrying too much about having the best stuff.
 
taylor rudd said:
i would recommend shooting within your means now and learning more about the craft. You could buy all the best glass - and some do - without knowing what they are paying for.

Start shooting, have fun, and grow in your skill before worrying too much about having the best stuff.
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+1!
 
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