Difference between cheap and expensive lens

[Edge100]

Another thing that many forget in their hunt for fast lenses is that a kit lens will look absolutely acceptable at around f/8, and a flash unit let's you make your own light and can be bought for much less than a f/2.8 zoom...

I'm a huge proponent of off-camera flash, but even I don't think flash is a substitute for fast glass. First off, many venues do not permit the use of flash. Second, if you don't have the shutter speed/f-stop/ISO speed to get a decent ambient exposure, you're going to end up with the dreaded "cave" look, where the subject is illuminated but the background is nearly black.

Flash is a useful addition to fast glass, but it is not a substitute for fast glass.

 

[Ruahrc]

If you are willing and/or able to use flash. Personally I much prefer the more natural look of available light photography (and even diffused/bounced flash leaves traces in the image). And when shooting indoor sports (or even outdoor sports when it's relatively dark) flash is not always that much use: it doesn't really have that much effect when the target is a reasonable distance away and sometimes flash is simply not acceptable.

I'm a huge proponent of off-camera flash, but even I don't think flash is a substitute for fast glass. First off, many venues do not permit the use of flash. Second, if you don't have the shutter speed/f-stop/ISO speed to get a decent ambient exposure, you're going to end up with the dreaded "cave" look, where the subject is illuminated but the background is nearly black.

Flash is a useful addition to fast glass, but it is not a substitute for fast glass.

These are valid arguments but frankly IMO for most people (myself included), a "preference for natural light" is really "inability/inexperience with flash or strobe lighting". One visit to a site like Joe McNally or the Strobist shows you that.

 

[Edge100]

These are valid arguments but frankly IMO for most people (myself included), a "preference for natural light" is really "inability/inexperience with flash or strobe lighting". One visit to a site like Joe McNally or the Strobist shows you that.

I 100% agree with you. Off-camera flash can look absolutely fantastic; so good, in fact, that it's often difficult to tell whether flash is being used at all. I couldn't agree with you more.

But that look can be difficult to achieve with slow lenses, if the ambient light reaching the sensor (which is determined by f-stop, shutter speed, and ISO) is insufficient. That is, the flash exposure could be perfect, but the ambient is so low that you get the "cave" look I described.

I'm 100% behind getting a flash (or three...) and learning to use them effectively. But I'm also 100% against using a flash as a de facto substitute for fast glass.

 

[Ruahrc]

You could even argue that the reverse is true- for those times that fast glass is appropriate, there are probably just as many times when strobes are the only way to get the correct shot (think fill flash and proper lighting balance), and trying to substitute strobes with fast glass is going to be just as disappointing.

 

[OreoCookie]

Another thing that many forget in their hunt for fast lenses is that a kit lens will look absolutely acceptable at around f/8, and a flash unit let's you make your own light and can be bought for much less than a f/2.8 zoom...

That's not correct, even then you'll have a big advantage with fast lenses: the flash only illuminates the foreground, the brightness of the background is determined by the aperture (unless you have a complicated multi-flash setup).

 

[Designer Dale]

So, everyone here works in the lens building business and are experts?
Or, lots of OJT from reading and buying $$'s.

I say that not attacking anyone, but at times I do question the big price difference between the "basic" lens and the "pro" lens.
---

I agree with most of this. What I wonder about is where the difference between quality 3rd party lenses like my Tamron 28-75 2.8 ($344 on Amazon) and the similar Canon L at $1350 from the same seller. Is the Red Ring really worth $1000?

Dale

 

[jackerin]

That's not correct, even then you'll have a big advantage with fast lenses: the flash only illuminates the foreground, the brightness of the background is determined by the aperture (unless you have a complicated multi-flash setup).

Aperture controls flash, shutter speed controls ambient. (Yes, I know technically aperture has a part in both, but when balancing lights that's what I like to keep in mind.)

If you can't set anything up then of course a fast lens will be preferrable. But considering bang-for-the-buck photography (not just image quality) it's hard to beat off-camera flash.

 

[Chiggs]

For what it's worth, I would add my perspective that the biggest difference between expensive and less expensive glass that can been seen by most people is the performance in low light conditions. I started with a D70 and the kit lens about 6-7 years ago. I traded my glass up to the 18-200 VR about 4 years ago and then traded my body up to the D300 about 3 years ago. I love taking pictures but was never happy with the pictures I was taking indoors in low light. I started out reading Ken Rockwell and while I think he has some good ideas on some subjects, resisted upgrading my glass for a year or so based on his writing that better glass won't let you take better pictures most of the time. Anyway, last week I took the plunge and picked up the Nikon 24-70 2.8. This past weekend, I used it for the first time on my D300 to take pictures of my new neice in natural indoors light. I was blown away - for the first time I felt as though my pictures were a fair representation of what my eyes saw. I'm thrilled with my new lens and expect that I will keep this glass for 10-15 years or more. I'll appreciate taking pictures with it long after I've forgotten how much I spent on the lens !!

 

[Edge100]

I agree with most of this. What I wonder about is where the difference between quality 3rd party lenses like my Tamron 28-75 2.8 ($344 on Amazon) and the similar Canon L at $1350 from the same seller. Is the Red Ring really worth $1000?

Dale

Well, the red ring...and the weather sealing, sharpness at f/2.8, and overall build quality; yes.

That said, there are some excellent alternatives to the Canon 24-70 f/2.8L; the new Sigma 24-70 f/2.8 HSM being one of them. The only issue is that it's priced at just slightly less than the Canon, AND you have to be sure you get a copy without any AF issues (FWIW, my Sigma 50 f/1.4 is perfect).

 

[Edge100]

Aperture controls flash, shutter speed controls ambient. (Yes, I know technically aperture has a part in both, but when balancing lights that's what I like to keep in mind.)

Aperture affects ambient exposure to the exact same degree as shutter speed and ISO. The "ambient = shutter, flash = aperture" moniker is a useful rule of thumb, but it's also only half true. It would be more accurate to say "shutter speed does not affect flash exposure" and leave it at that.

 

[OreoCookie]

Aperture controls flash, shutter speed controls ambient. (Yes, I know technically aperture has a part in both, but when balancing lights that's what I like to keep in mind.)

It's the exposure, i. e. the combination of shutter speed, aperture and ISO, that controls the ambient light: unless the background is very close to the subject, you get a good idea of what the background will look like if you take a picture without flash and then check it on the lcd. Of course, this is only an indication since flash light spills onto other objects, but it gives you something to work with.

In practical situations, you're limited to a narrow band of shutter speeds, though, something like 1/60 s to 1/30 s on a 30 mm crop sensor/50 mm full frame. If you have a slow lens, you may not be able to attain those shutter speeds and hence my comment that in this instance, lenses with larger aperture are not replaceable by flash.

If you can't set anything up then of course a fast lens will be preferrable. But considering bang-for-the-buck photography (not just image quality) it's hard to beat off-camera flash.

I don't think so, it depends on what kind of light you actually want to have. In a club or a bar, you maybe want those neon colors -- which are all but destroyed if you use off-camera flash for the background. I like using off-camera flash, but there are situations when it's better to use ambient light. Other times, the background may be at infinity (a city skyline, for instance) which you won't be able to light either.

Plus, an external flash is not cheaper than a nifty-fifty or a 30 mm/35 mm prime.

 

[OreoCookie]

It would be more accurate to say "shutter speed does not affect flash exposure" and leave it at that.

Are you referring to the tendency of flash to freeze motion, i. e. that you will have less motion blur?

 

[pprior]

I think the argument about fill flash substituting for fast glass is a bit misleading. These give totally different looks.

You can't fill flash the background. You can't fill flash a baseball field at twilight. You can't focus faster with fill flash.

Yes you can get a snapshot at the family reunion with flash, and yes if you're shooting at F5.6 you'll probably need it. But these are very different.

On the flip side, fast glass doesn't help fill shadows on the face and doesn't help accentuate the subject against the BG like flash can do.

I'm not anti-flash, I use them creatively, but it's really apples and oranges, IMO.

If I had to pick 2 from my list above of what keeps ME buying expensive L glass it's the BG blur and the ability to shoot ambient action sports. And the contrast/sharpness, and the quality build...

Keep in mind that canon L glass holds it's value pretty well, I've owned some lenses and sold them later and for the time I used them it was only a difference of a few hundred bucks. Another difference in the red stripe is no firmware updates or incompatibility problems which you can see with off labels stuff.

 

[Edge100]

Are you referring to the tendency of flash to freeze motion, i. e. that you will have less motion blur?

No; I'm referring to the fact that shutter speed has absolutely no effect on flash exposure.

Try this: with your lens set to ISO 200, f/5.6, 1/50s, set your flash to manual mode and choose, say, 1/8 power (or less if you're getting complete blowout). Take an exposure. Now change shutter speed to 1/200s; your ambient exposure is two stops lower, but the flash exposure looks exactly the same.

This is because the flash pulse is MUCH faster than the shutter speed.

Remember, using flash means you have two exposures; one for the ambient and one for the flash. The ambient is controlled normally (i.e. aperture, shutter speed, and ISO each have equivalent effects), while flash exposure is controlled only by aperture and ISO (along with flash power and flash-to-subject distance, but not shutter speed).

 

[Edge100]

I'm not anti-flash, I use them creatively, but it's really apples and oranges, IMO.

Well put.

Keep in mind that canon L glass holds it's value pretty well, I've owned some lenses and sold them later and for the time I used them it was only a difference of a few hundred bucks. Another difference in the red stripe is no firmware updates or incompatibility problems which you can see with off labels stuff.

Again, well put. And if you buy used glass from a reputable source, the cost of ownership is essentially zero (well, minus the opportunity cost, I suppose); you can sell the lens for the same amount you bought it for (or sometimes more...this has happened to me twice).

 

[OreoCookie]

No; I'm referring to the fact that shutter speed has absolutely no effect on flash exposure.

Oh, this, yeah. As you say, it's because the flash pulse is much quicker than the exposure time.

… while flash exposure is controlled only by aperture and ISO (along with flash power and flash-to-subject distance, but not shutter speed).

Yup. Although in practice, if you use TTL, then the camera takes flash-to-subject distance, aperture and ISO into account and varies the flash power accordingly.

 

[Edge100]

Yup. Although in practice, if you use TTL, then the camera takes flash-to-subject distance, aperture and ISO into account and varies the flash power accordingly.

Yes; with ETTL (I guess iTTL is the Nikon equivalent???), the camera does all the calculations. You can change f-stop, ISO, and flash-to-subject distance all you like and you wont get a change in flash exposure; within certain limits, of course...if you exceed the guide number of the flash (GN = f-stop x flash-to-subject distance) you'll get underexposed images.

The only way to change the flash exposure in ETTL mode is to ride the flash exposure compensation.

 

[carlgo]

As one who only gets a technically good flash photo once in a while...anyway, I have been trying more fill flash and it can be quite good when it is good. I took some of kids and got a sparkle in their eyes and the skin tones were great. Use it more all the time and the results are getting fairly good a predictable.

And, don't forget that you can use diffusers and gels and such to modify the lighting.

There are times when a flash can substitute for a faster lens, but obviously not always. But if all you have is a smaller and lighter lens, and there are very good reasons to own these, then a flash can bail you out and all is good.

Modern cameras are so good with flash that it is a shame not to use it. Some of us remember dials and calculations...good reasons to avoid it.

 

[mtbdudex]

So, have we answered the OP's Q's?
I added 1, 2, 3. Every few months this Q comes up, members chime in, and we move on to other...discussions....

I'm new to photography, and am reading a lot about how people will pay thousands of dollars for a lens because its really high quality and produces superior images.

1) What though is different between the really expensive high-end lens and a cheap one in terms of image quality?

I understand expensive lens are probably made better and thus are more durable and will last years longer.

2) However, in terms of just the image the lens will produce, is a high end lens any better than a cheap one?

3) If the image is better, what makes it that way, the glass itself in the lens?

My take:
1) answered
2) answered, there are fact based technical graphs to show also if need be
3) answered

Now, fwiw I'd like to save $2k for the latest 70-200 2.8 IS L by Canon, that is my "dream" lens, maybe spring 2011 splurge.

 

[Edge100]

Now, fwiw I'd like to save $2k for the latest 70-200 2.8 IS L by Canon, that is my "dream" lens, maybe spring 2011 splurge.

Do it! I have heard nothing but high praise for that lens; the sharpness of the 70-200 f/4L IS, with the added stop to boot.

 

[mtbdudex]

Do it! I have heard nothing but high praise for that lens; the sharpness of the 70-200 f/4L IS, with the added stop to boot.

Then I'd add the newly released $500 1.4TC and have all the reach and speed I can get from modern optics.

 

[Full of Win]

These are valid arguments but frankly IMO for most people (myself included), a "preference for natural light" is really "inability/inexperience with flash or strobe lighting". One visit to a site like Joe McNally or the Strobist shows you that.

Please

Natural light and shadow have a quality all their own. It jsut depends on the look you are going for.

 

[Edge100]

Natural light and shadow have a quality all their own. It jsut depends on the look you are going for.

That's true; but the point is, I think, still valid. Many people are averse to using flash because they don't know how to use flash effectively. That's not an argument for using natural light; it's an argument for learning to use flash effectively.

FWIW, for anyone looking to use on-camera flash effectively (that is, hotshoe mounted flash...not pop-up flash), there is no better resource than Neil van Niekerk's blog 'Tangents'.

For off-camera flash, you need to get over to Strobist and pick up 'The Moment it Clicks' and 'The Hotshoe Diaries', both by Joe McNally.

 

[jackerin]

Aperture affects ambient exposure to the exact same degree as shutter speed and ISO. The "ambient = shutter, flash = aperture" moniker is a useful rule of thumb, but it's also only half true. It would be more accurate to say "shutter speed does not affect flash exposure" and leave it at that.

I thought I mentioned that I already knew that, but ok. In return I will correct you in saying that shutter speed affects flash exposure in that the max sync speed is usually around 1/200 (when not using TTL HSS or CCD sensors).

Edit: the above was probably a bit snarky, but I'll leave it in case anyone wants to take issue with it.

Other times, the background may be at infinity (a city skyline, for instance) which you won't be able to light either.

In this situation I would go for a longer exposure and use second-curtain flash and see what results I get. (If I only had a flash, that is.)

 

[a.jfred]

That's true; but the point is, I think, still valid. Many people are averse to using flash because they don't know how to use flash effectively. That's not an argument for using natural light; it's an argument for learning to use flash effectively.

Which is all well & good, and like most things, something that only lots of practice can really resolve. But on the flip side of that argument, there's the one that says "learn to expose your photo correctly the first time" - far too many people fall in the other camp: using flash for every.single.picture.

And FWIW, while I'm a big fan of "expose correctly" and "ambient light," I do occasionally use flash, and play with it until I get it right. Flash has a purpose in my photography; it's just not something I use often.