Why still big glass?

Nico Westerman · Dec 17, 2004

Of course big (white) lenses are impressive. But I myself, I prefer to shoot as unnoticed as possible. In former days the argument for lenses with big glass was always that the bigger the glass, the better the central part of it. Back in the very early eighties I had the first Canon SLR with program, the A1 I think it was. And together with it (no zooms in that time) a 28 2,8; a 200 2,8 and a 50 mm 1,0 (only the last one weighted almost a kilo)! I took this with me on long trips to India, Sri Lanka, Indonesia, Malaysia and Thailand. And good heaven, what was it heavy altogether! What did I suffer!

Using 35 mm lenses in digital photography means that you don’t use the periphery of your lens. Further question is: is it still true that the central part of lenses with a bigger glass sur-face is optically better than the central part of more expensive lenses with a slower dia-phragm? I think I have never used my old 50 mm 1.0 wide open, probably I never used it below 2,8. Below that there is simply no DOF, or DOF is so shallow that for most purposes it is unfit. For portraits I mostly work at 4,0 or even 5,6. Of course I want the background to be out of focus. But I hate it when the nose is sharp but the ear is not. Big glass is still almost as heavy as it was in the old days – although plastic diminishes the burden at the cost of what it is: plastic. Lenses with 1,0 are not available anymore as far as I know. But I see a lot of peo-ple still choosing for 2,8 lenses and with primes still go tot 1,4 if available. Why is this? What after all is the purpose of 1,4 in low light photography? Even when the podium is far away, the needed DOF will always be more than can be shot with 1,4 wide open. Is not one of the great advantages of AS that it permits in low light situations to shoot out of the hand at 4,0, 5,6 or even 8,0? At least when the target is not moving. And is 2,8 or bigger needed when the target is moving? Shooting at 5,6 with a ‘fast’ 2,8 white lens, takes the same shutter tine as with a ‘slow’ 4,0 lens at the same diaphragm. And DOF is the same in both situations. Or am I missing something? When I asked advise at the forum for choosing the Minolta 28-75 2,8 or the 24-105 3,5–4,5 when buying the camera, I got the advise to take the 28-75. Not only be-cause it should be sharper – which of course I consider a proper argument – but because I would meet circumstances in which 2,8 was needed. Of course there is the advantage that the viewfinder is brighter. But the viewfinder of the 7D is so good that – in my opinion – this can not be the reason for big glass. So I don’t mind that the Sigma 12-24 is ‘only’ 4,5-5,6. I mind that it is 615 gram. Of course: in tele you can shoot wide open with a good lens, and without doubt there a fast diaphragm was definitely an advantage. But since there is AS is it not: was…. When I decide to buy the D7, I might decide to buy as well a nice 70-200 (if I am not broke by the time). But only for the reason that it is remarkably sharper than my 100-300 D. Not anymore because it is 2,8. Not with AS. I would generally state that AS takes away the need of having to carry 6 kilo for a simple Sunday morning walk in the park.
So after all I have said: my question: why still big glass?

I highly welcome your views, and wrote this post by no means to offend anybody who likes or uses big glass, but just to learn something. Nico Westerman.

morris · Dec 17, 2004

Nico,

Different types of photography call for different equipment. Yes IS reduces the need for fast lenses to work in low light, but at the same time it allows you to work in lower light. So dose a tripod. I think you need to look at lenses for there application and decide what is important.

Landscape: Well what do you need a fast lens for, you will be shooting closed down all the way.

Wildlife: Long telephotos are the name of the game and they never seem long enough or fast enough when the light gets dim which is when the best opportunities are. Try and shoot flight photos at sunrise or sunset and you will see my point.

Street photography: Well now it’s time for every focal length and lighting situation you can think of. Either you carry a pile of lenses or you chose a fun lens like a 28-300 with macro. Yep, there not as sharp or as fast, but you don’t miss opportunities changing lenses. IS shines for this.

Sports: Close to wildlife, but you don’t need infinite reach if you get good position.

Macro: DOF is a roil pain but you need enough to isolate the subject.

As for your question about the middle of a lens. Well on top lenses it dose not matter much, but on a cheep lens the middle is the good part and using a lens that has a good middle but moderate edges can save you big bucks when used on a 1.5 FOV digital.

I’ve got a bunch of FD lenses and cameras sitting around. I always chose lighter lenses as I do plenty of hiking.

Morris
--

http://qcpages.qc.edu/~morris/POD

Sol · Dec 17, 2004

Hi Nico,
Up close, with beautiful bokeh, is the simple answer.

This is the Sigma 70-200 2,8 EX. I wish I had nailed the focus on the eyes better, and it is a tad under-exposed, but you can still see the beautiful bokeh this lens can create. As it crushes the background detail, it blends those colors into this really soft multi-colored backdrop for the subject.

The same applies here as far as the bokeh is concerned. But this is with the Tamron 300 2.8 SP IF LD. This a really great lens! And as you can see that crushed soft colors "backdrop", really sets off the subject. It makes the squirrel look that much sharper, compared to the background.

Hope this helped Nico.

Nico Westerman said:
Of course big (white) lenses are impressive. But I myself, I prefer
to shoot as unnoticed as possible. In former days the argument for
lenses with big glass was always that the bigger the glass, the
better the central part of it. Back in the very early eighties I
had the first Canon SLR with program, the A1 I think it was. And
together with it (no zooms in that time) a 28 2,8; a 200 2,8 and a
50 mm 1,0 (only the last one weighted almost a kilo)! I took this
with me on long trips to India, Sri Lanka, Indonesia, Malaysia and
Thailand. And good heaven, what was it heavy altogether! What did I
suffer!
Using 35 mm lenses in digital photography means that you don’t use
the periphery of your lens. Further question is: is it still true
that the central part of lenses with a bigger glass sur-face is
optically better than the central part of more expensive lenses
with a slower dia-phragm? I think I have never used my old 50 mm
1.0 wide open, probably I never used it below 2,8. Below that there
is simply no DOF, or DOF is so shallow that for most purposes it is
unfit. For portraits I mostly work at 4,0 or even 5,6. Of course I
want the background to be out of focus. But I hate it when the nose
is sharp but the ear is not. Big glass is still almost as heavy as
it was in the old days – although plastic diminishes the burden at
the cost of what it is: plastic. Lenses with 1,0 are not available
anymore as far as I know. But I see a lot of peo-ple still choosing
for 2,8 lenses and with primes still go tot 1,4 if available. Why
is this? What after all is the purpose of 1,4 in low light
photography? Even when the podium is far away, the needed DOF will
always be more than can be shot with 1,4 wide open. Is not one of
the great advantages of AS that it permits in low light situations
to shoot out of the hand at 4,0, 5,6 or even 8,0? At least when
the target is not moving. And is 2,8 or bigger needed when the
target is moving? Shooting at 5,6 with a ‘fast’ 2,8 white lens,
takes the same shutter tine as with a ‘slow’ 4,0 lens at the same
diaphragm. And DOF is the same in both situations. Or am I missing
something? When I asked advise at the forum for choosing the
Minolta 28-75 2,8 or the 24-105 3,5–4,5 when buying the camera, I
got the advise to take the 28-75. Not only be-cause it should be
sharper – which of course I consider a proper argument – but
because I would meet circumstances in which 2,8 was needed. Of
course there is the advantage that the viewfinder is brighter. But
the viewfinder of the 7D is so good that – in my opinion – this can
not be the reason for big glass. So I don’t mind that the Sigma
12-24 is ‘only’ 4,5-5,6. I mind that it is 615 gram. Of course: in
tele you can shoot wide open with a good lens, and without doubt
there a fast diaphragm was definitely an advantage. But since
there is AS is it not: was…. When I decide to buy the D7, I might
decide to buy as well a nice 70-200 (if I am not broke by the
time). But only for the reason that it is remarkably sharper than
my 100-300 D. Not anymore because it is 2,8. Not with AS. I would
generally state that AS takes away the need of having to carry 6
kilo for a simple Sunday morning walk in the park.
So after all I have said: my question: why still big glass?

I highly welcome your views, and wrote this post by no means to
offend anybody who likes or uses big glass, but just to learn
something. Nico Westerman.

--
Sol
'Charter Member of the Konica Minolta 7D Adoption Society'

'IS' will make your lens a better lens.
'VR' will make your lens a better lens.
'AS' will make you a better Photographer.

Dennis · Dec 17, 2004

Nico Westerman said:
So after all I have said: my question: why still big glass?

It seems that you answered the question in your own post. You stated that you "mostly" shoot stopped down a little and that AS helps "at least" when subject motion isn't an issue ... you acknowledge the brighter viewfinder.

I personally do shoot my 50/1.4 wide open ... if that's what it takes to get a fast enough shutter speed, I'll sacrifice DOF. I shoot a lot of candids of people where subject blur is a problem at 1/30s or slower. I frequently shoot my 100/2.8 wide open. I almost always shoot my 400/4.5 wide open and frequently wish it were an f/2.8 ! Honestly, I expect high ISO to be more beneficial than AS in this regard. Look at it this way: Canon users say AS is unnecessary because of high ISO. Minolta users say AS is just one more option. So wouldn't fast lenses be yet another option ? And don't underestimate the benefit of that brighter VF, and don't forget that DOF on the 7D will be a little bit greater since you compose with a shorter focal length than on 35mm.

I think that due to high ISO capabilities and AS, fast lenses are needed to cover fewer shooting situations than before. But with those capabilities, that same fast glass covers even more shooting situations than before.

Dennis

Nico Westerman · Dec 17, 2004

Thanks Sol. Great pictures. The squirrel is fantastic with a bokeh of melted cheese! And probably you took both the images wide open at 2,8. But is 2,8 or wider really a must to get a good bokeh? Could a slower but good quality lens with a circular aperture not give the same beautifull bokeh?

Of course what Dennis writes is completely true. Foveal multiplication enlarges the DOF of a lens at the cost of bokeh. And of course there is another reason for a fast lens with action: you can freeze the action. AS is of no help for that, but high ISO will make freezing much more easy. But I have never been such an action shooter. So by asking the question I didn’t think of action photography. Nico.

Sol said:
Hi Nico,
Up close, with beautiful bokeh, is the simple answer.

Nico Westerman · Dec 17, 2004

Hi Morris, thanks for replying.

morris said:
Nico,

Different types of photography call for different equipment. Yes
IS reduces the need for fast lenses to work in low light, but at
the same time it allows you to work in lower light. So dose a
tripod. I think you need to look at lenses for there application
and decide what is important.

Landscape: Well what do you need a fast lens for, you will be
shooting closed down all the way.

Wildlife: Long telephotos are the name of the game and they never
seem long enough or fast enough when the light gets dim which is
when the best opportunities are. Try and shoot flight photos at
sunrise or sunset and you will see my point.

Yes I understand. And I completely agree with the necessity of a long lens in wild life photog-raphy. But my remark was not the focal length - although I would think that an advance of digital photography above film is that you can crop - but the diaphragm. But would you not think that the combination of high ISO and AS can make the difference between 300 2,8 and 300 4,5?

Member said:
Street photography: Well now it’s time for every focal length and
lighting situation you can think of. Either you carry a pile of
lenses or you chose a fun lens like a 28-300 with macro. Yep,
there not as sharp or as fast, but you don’t miss opportunities
changing lenses. IS shines for this.

I am thinking about the 24-105. Gives 36-157,5 and is probably more than just a fun lens.

Member said:
Sports: Close to wildlife, but you don’t need infinite reach if you
get good position.

Macro: DOF is a roil pain but you need enough to isolate the subject.

I agree in macro. In my shallow experience with macro light is a crucial factor. Even if you shoot at diafragm38. I was thinking of the 100 mm 2,8 here.

Member said:
As for your question about the middle of a lens. Well on top
lenses it dose not matter much, but on a cheep lens the middle is
the good part and using a lens that has a good middle but moderate
edges can save you big bucks when used on a 1.5 FOV digital.

I’ve got a bunch of FD lenses and cameras sitting around. I always
chose lighter lenses as I do plenty of hiking.

Yes, I don’t want to carry around big weight anymore.

Nico.

Sol · Dec 17, 2004

Hey Nico,

Nico Westerman said:
Thanks Sol. Great pictures. The squirrel is fantastic with a bokeh
of melted cheese! And probably you took both the images wide open
at 2,8. But is 2,8 or wider really a must to get a good bokeh?
Could a slower but good quality lens with a circular aperture not
give the same beautifull bokeh?

Well, not to say you can't get "good' bokeh at another focal length and aperture setting, but generally speaking, the wider your aperture, the better the bokeh gets. And by the same token, the closer you get to your subject, at any given focal length, the better the bokeh gets.

And yes, a slower, but better quality lens can still, give you a very good bokeh effect.

Nico Westerman said:
Of course what Dennis writes is completely true. Foveal
multiplication enlarges the DOF of a lens at the cost of bokeh. And
of course there is another reason for a fast lens with action: you
can freeze the action. AS is of no help for that, but high ISO will
make freezing much more easy. But I have never been such an action
shooter. So by asking the question I didn’t think of action
photography. Nico.

Sol said:

Hi Nico,
Up close, with beautiful bokeh, is the simple answer.

Click to expand...

--
Sol
'Charter Member of the Konica Minolta 7D Adoption Society'

'IS' will make your lens a better lens.
'VR' will make your lens a better lens.
'AS' will make you a better Photographer.

Nico Westerman · Dec 17, 2004

hi Dennis,

Yes I understand. In my consideration that fast lenses may be are not necessary anymore, I had forgotten the need of freezing action in candid photography. Which in fact I do a lot too. And yes of course: high ISO will be very helpful here too. So maybe it will be possible to sacrifice a little less DOF. Will probably bring out a greater percentage of successful images.

I understand that with you last remark about the foveal multiplication factor, you probably mean that you get a less beautiful bokeh?
Greetings, Nico

Dennis said:
It seems that you answered the question in your own post. You
stated that you "mostly" shoot stopped down a little and that AS
helps "at least" when subject motion isn't an issue ... you
acknowledge the brighter viewfinder.

I personally do shoot my 50/1.4 wide open ... if that's what it
takes to get a fast enough shutter speed, I'll sacrifice DOF. I
shoot a lot of candids of people where subject blur is a problem at
1/30s or slower. I frequently shoot my 100/2.8 wide open. I
almost always shoot my 400/4.5 wide open and frequently wish it
were an f/2.8 ! Honestly, I expect high ISO to be more beneficial
than AS in this regard. Look at it this way: Canon users say AS is
unnecessary because of high ISO. Minolta users say AS is just one
more option. So wouldn't fast lenses be yet another option ? And
don't underestimate the benefit of that brighter VF, and don't
forget that DOF on the 7D will be a little bit greater since you
compose with a shorter focal length than on 35mm.

I think that due to high ISO capabilities and AS, fast lenses are
needed to cover fewer shooting situations than before. But with
those capabilities, that same fast glass covers even more shooting
situations than before.

Dennis

Dennis · Dec 17, 2004

Nico Westerman said:
Thanks Sol. Great pictures. The squirrel is fantastic with a bokeh
of melted cheese! And probably you took both the images wide open
at 2,8. But is 2,8 or wider really a must to get a good bokeh?
Could a slower but good quality lens with a circular aperture not
give the same beautifull bokeh?

While I prefer circular apertures for the appearance of specular highlights, it's not essential for good bokeh. Nor is shooting wide open - you just need OOF areas and a lens with ... well ... good bokeh ! I get great OOF areas from my macro lenses - particularly the 200/4 which I've been shooting much more often - stopped down to f/16 to get the subject in focus. Bokeh is the appearance of OOF areas ... if you can't get shallow enough DOF to have OOF areas, bokeh isn't really an issue (or is perceived as "ugly" if focus is sufficient to make out distracting background details. So, in my view, bokeh is a component of an image. The characteristics of the lens, the specific settings, and the composition all contribute. Lenses that are considered to have "good bokeh" can produce images with lousy bokeh if the background is too close & complex.

Nico Westerman said:
Of course what Dennis writes is completely true. Foveal
multiplication enlarges the DOF of a lens at the cost of bokeh. And
of course there is another reason for a fast lens with action: you
can freeze the action. AS is of no help for that, but high ISO will
make freezing much more easy.

Nico Westerman said:
But I have never been such an action
shooter. So by asking the question I didn’t think of action
photography. Nico.

Me neither. I like fast long lenses, because I humor myself with the notion of photographing wildlife. Seriously, I do get out in the early morning from time to time, and photograph deer, birds, whatever else I can find, in low light. The 400/4.5 is about as sharp at f/4.5 as it is at f/8; sharp from corner to corner (not hard when the FOV is so small !) and I frequently shoot at around 1/30s (ISO 50 or 100 film whenever possible) ... shooting frame after frame to maximize the odds of getting a shot where the subject doesn't blur. Throw in a polarizer and you need a still subject or good luck (or brighter light). I'll shoot Provia 400 if I know I'll be shooting wildlife, but generally don't want to put a 36-exp roll in the camera. The f/4.5 is sort of "big glass". At US$1900 new, with a drop-in filter holder, rotating tripod collar, and industrial construction, it qualifies, and it's a bit faster than the 3rd party f/5.6s. It's slow enough that I'd love an f/2.8 from time to time. I'm really looking forward to the ability to routinely bump up the ISO to 400 and occasionally bump it up to 800 or 1600. AS wouldn't help at all, since I don't shoot it handheld.

As mentioned, I shoot the 100/2.8 and 200/2.8 wide open ... and DOF is generally sufficient and will be more so with the APS sensor.

As for the 50/1.4, with ISO 400 film, I've taken it out and shot handheld evening shots in tourist spots at around 1/30. These typically have shallower DOF than I'd like, and would benefit from AS even at that shutter speed. I look forward to shooting those w/AS and possibly increasing ISO to stop down a bit. But being able to open up to f/1.4 gives me even more options. Honestly, at f/1.4, the lens is somewhat soft, and I probably would have saved money and bought the f/1.7, except I like the bayonet lens shade and the 55mm filter thread. When it comes to WAs, I've never cared anout lens speed, as I typically always used them on a tripod or in bright daylight. The same will probably hold true with the 7D, though a fast 35mm would be nice (for the same reasons as a fast 50mm with film ... the FOV crop will put a crimp on some of my low light shooting with that lens, but also open up other options).

I can easily see some photographers not needing faster-than-f/4 lenses for their APS DSLR work.

Dennis

Dennis · Dec 17, 2004

Nico Westerman said:
I understand that with you last remark about the foveal
multiplication factor, you probably mean that you get a less
beautiful bokeh?

Well, my point was really that, if you currently avoid wide apertures on 35mm because of too-shallow DOF, you can probably expand your horizons a little with the 7D, shooting faster and maintaining the same DOF (and, possibly, same bokeh, depending on what lens you're using).

Dennis

Karl Gnter Wnsch · Dec 17, 2004

Another reason for wide apertures, besides the already well put bokeh and subject isolating properties, is the AF. On many cameras the AF is specified to render the selected focus point within the DOF of the lens used wide open. As the larger aperture is producing a much smaller DOF the AF is thus more precise and can reliably work at lower EV shooting conditions. A f/5.6 lens is much more likely to hunt for a good focus than a f/1.4 lens at all but the best of circumstances.
--
regards
Karl Günter Wünsch

Sol · Dec 17, 2004

Hey Dennis, Lots of good input here, man.

Dennis said:
Dennis said:

Nico Westerman wrote:
Thanks Sol. Great pictures. The squirrel is fantastic with a bokeh
of melted cheese! And probably you took both the images wide open
at 2,8. But is 2,8 or wider really a must to get a good bokeh?
Could a slower but good quality lens with a circular aperture not
give the same beautifull bokeh?

Click to expand...

While I prefer circular apertures for the appearance of specular
highlights, it's not essential for good bokeh. Nor is shooting
wide open - you just need OOF areas and a lens with ... well ...
good bokeh ! I get great OOF areas from my macro lenses -
particularly the 200/4 which I've been shooting much more often -
stopped down to f/16 to get the subject in focus. Bokeh is the
appearance of OOF areas ... if you can't get shallow enough DOF to
have OOF areas, bokeh isn't really an issue (or is perceived as
"ugly" if focus is sufficient to make out distracting background
details. So, in my view, bokeh is a component of an image. The
characteristics of the lens, the specific settings, and the
composition all contribute. Lenses that are considered to have
"good bokeh" can produce images with lousy bokeh if the background
is too close & complex.

I agree with you, Dennis. Bokeh is certainly a component of image. Depending on what the background is doing, even the best of lenses can create useless bokeh. Bokeh is what the lens does to the OOF areas. If you are using a high aperture setting, than the DOF is huge, pretty much leaving no out of focus areas to create bokeh. I assume when you mentioned your 200/4 at f/16, you are pretty tight on your subject, as in a macro situation, correct? I did try to reference to Nico, the factor that regardless of focal length, the closer you get to the subject the more OOF areas become a factor. And thus better chance for bokeh. maybe I didn't explain it well enough. Sorry.
Here's the simpler definition, for those who are curious.
http://www.nemeng.com/leica/014e.shtml
Here's a more in depth definition.
http://www.kenrockwell.com/tech/bokeh.htm

Dennis said:
Dennis

--
Sol
'Charter Member of the Konica Minolta 7D Adoption Society'

'IS' will make your lens a better lens.
'VR' will make your lens a better lens.
'AS' will make you a better Photographer.

Dennis · Dec 17, 2004

Sol said:
Hey Dennis, Lots of good input here, man.

Thanks Sol

I've been following your posts on your 7D experience (and enjoying your pics, too).

Sol said:
I did try to
reference to Nico, the factor that regardless of focal length, the
closer you get to the subject the more OOF areas become a factor.
And thus better chance for bokeh.

Exactly ! Photography is all about compromises ... maybe A/S and high ISO capabilities narrow the window for conditions where fast lenses are needed. But they don't shut it. They still offer you options for shallower-DOF (contributing to more OOF backgrounds, as you said), faster shutter speeds, lower ISO, lower lighting ... and, of course, that brighter VF image

Dennis

JusGene · Dec 17, 2004

that what you say will affect the OOF/backfocus situation so many 7D owners talk about?

Thanks,

Gene

Karl Günter Wünsch said:
Another reason for wide apertures, besides the already well put
bokeh and subject isolating properties, is the AF. On many cameras
the AF is specified to render the selected focus point within the
DOF of the lens used wide open. As the larger aperture is producing
a much smaller DOF the AF is thus more precise and can reliably
work at lower EV shooting conditions. A f/5.6 lens is much more
likely to hunt for a good focus than a f/1.4 lens at all but the
best of circumstances.
--
regards
Karl Günter Wünsch

--
JusGene
'The easiest thing you can be ... is wrong!' -Me (7/29/1993)
'Statistically, people make mistakes 70% of the time' -Independent Research Firm
'The more you know, the more you don't know' -Me (8/14/1987)
'Life is nothing, but for a bunch of words' -Me (11/4/1990)
RD-175, X-9, 450si(DATE), SPxi, Mamiya 645, D7u

Jay Williams · Dec 17, 2004

Nico Westerman said:
But I hate it when the nose is sharp but the ear is not.

If the eyes are sharp, you'll forget about the rest--nose, ears, and all.

Nico Westerman said:
Even when the podium is far away, the needed DOF will
always be more than can be shot with 1,4 wide open.

If the subject if far away, you'll have good DOF, even at f/1.4. Like some of the other posters pointed out, if you focus close, you have shallow DOF. Conversely, if you focus far, you'll have great DOF. The way I like to look at it, high magnification equals shallow DOF. Low magnification equals great DOF.

Nico Westerman said:
Is not one of the great advantages of AS that it permits in low light > situations to shoot out of the hand at 4,0, 5,6 or even 8,0? At least > when the target is not moving.

That's key. If the target is moving, AS won't save you. And using a faster lens is, to many people, preferable to using higher ISO.

Nico Westerman said:
the viewfinder of the 7D is so good that – in my opinion – this can
not be the reason for big glass.

No matter how good the viewfinder, the faster the lens, the brighter the viewfinder.

There are some additional good points made by other posters which I won't regurgitate.

In summary, there are a lot of good reasons for using big glass.

Jay
http://www.jpwphoto.com

Mark K · Dec 17, 2004

Nico Westerman said:
Of course big (white) lenses are impressive.

Did you mean the quality or you meant the size？

Nico Westerman said:
But I myself, I prefer to shoot as unnoticed as possible. In former days the argument for
lenses with big glass was always that the bigger the glass, the
better the central part of it. Back in the very early eighties I
had the first Canon SLR with program, the A1 I think it was. And
together with it (no zooms in that time) a 28 2,8; a 200 2,8 and a
50 mm 1,0 (only the last one weighted almost a kilo)! I took this
with me on long trips to India, Sri Lanka, Indonesia, Malaysia and
Thailand. And good heaven, what was it heavy altogether! What did I
suffer!

I carried A1, too, to China but with a 28-200. The images were terrible

Nico Westerman said:
Using 35 mm lenses in digital photography means that you don’t use
the periphery of your lens. Further question is: is it still true
that the central part of lenses with a bigger glass sur-face is
optically better than the central part of more expensive lenses
with a slower dia-phragm?

Obviously the bigger glass offers far better image quality

Nico Westerman said:
I think I have never used my old 50 mm
1.0 wide open, probably I never used it below 2,8. Below that there
is simply no DOF, or DOF is so shallow that for most purposes it is
unfit. For portraits I mostly work at 4,0 or even 5,6. Of course I
want the background to be out of focus. But I hate it when the nose
is sharp but the ear is not. Big glass is still almost as heavy as
it was in the old days – although plastic diminishes the burden at
the cost of what it is: plastic. Lenses with 1,0 are not available
anymore as far as I know. But I see a lot of peo-ple still choosing
for 2,8 lenses and with primes still go tot 1,4 if available. Why
is this? What after all is the purpose of 1,4 in low light
photography? Even when the podium is far away, the needed DOF will
always be more than can be shot with 1,4 wide open. Is not one of
the great advantages of AS that it permits in low light situations
to shoot out of the hand at 4,0, 5,6 or even 8,0? At least when
the target is not moving. And is 2,8 or bigger needed when the
target is moving? Shooting at 5,6 with a ‘fast’ 2,8 white lens,
takes the same shutter tine as with a ‘slow’ 4,0 lens at the same
diaphragm. And DOF is the same in both situations. Or am I missing
something? When I asked advise at the forum for choosing the
Minolta 28-75 2,8 or the 24-105 3,5–4,5 when buying the camera, I
got the advise to take the 28-75. Not only be-cause it should be
sharper – which of course I consider a proper argument – but
because I would meet circumstances in which 2,8 was needed. Of
course there is the advantage that the viewfinder is brighter. But
the viewfinder of the 7D is so good that – in my opinion – this can
not be the reason for big glass. So I don’t mind that the Sigma
12-24 is ‘only’ 4,5-5,6. I mind that it is 615 gram. Of course: in
tele you can shoot wide open with a good lens, and without doubt
there a fast diaphragm was definitely an advantage. But since
there is AS is it not: was…. When I decide to buy the D7, I might
decide to buy as well a nice 70-200 (if I am not broke by the
time). But only for the reason that it is remarkably sharper than
my 100-300 D. Not anymore because it is 2,8. Not with AS. I would
generally state that AS takes away the need of having to carry 6
kilo for a simple Sunday morning walk in the park.
So after all I have said: my question: why still big glass?

I share the same feelings as you and had always believed that DSLR gives me freedom, freedom from carrying all these big glass optics and I will be able to use all these wonderful small sized lenses.
I bought 18-128 for D70 and 24-135/2.8-4.5 for D7D

I also took out my year old Minolta 70-210/4 for a shooting, in favour of its smaller size and rave reivews. I took out a Minolta 2.8/G yesterday for a comparative study.

The result is, too obviuos. Faster lenses esp those prime lenses, offer far better optical quality on DSLR.

Nico Westerman said:
I highly welcome your views, and wrote this post by no means to
offend anybody who likes or uses big glass, but just to learn
something. Nico Westerman.

--
Mark K
7d, 20/2.8, 50/2.8 macro, 50/1.7, 85/1.4G, 100/2.8 soft, 100/2.8 macro, 200/2.8G

Michael Meissner · Dec 17, 2004

Jay Williams said:
That's key. If the target is moving, AS won't save you. And using a
faster lens is, to many people, preferable to using higher ISO.

Yes and no. If you have a 250mm lens, by the usual rule of thumb you need a shutter speed of 1/250 to photograph it without camera shake (obviously this is only a rule of thumb and depends on many variables). With AS giving you 2-3 f/stops, that means you could still photograph the scene at 1/60 (2 f/stops) or possibly 1/30 (3 f/stops). Yeah, 1/60 may not be fast enough to catch some small children, but for many situations it is sufficient.

Karl Gnter Wnsch · Dec 18, 2004

JusGene said:
that what you say will affect the OOF/backfocus situation so many
7D owners talk about?

Probably not. A misaligned sensor is a misaligned sensor and it will show up more prominently if the DOF is shallow. Stopping down the lens heavily would mask this effect but not get rid of it.

The thing that Minolta probably hit cold here was the effect that the larger your prints (and viewing at 100% in photoshop qualifies as a A3/A2 sized print when factoring in the viewing distance) the shallower the DOF becomes. So if (like other manufacturers) the AF is specced to be within 1 DOF (only Canon 1D?, 20D(in high precision mode) and Nikon D1/D2 have a specification of 1/3rd DOF IIRC) then you'd have to look up which size print they considered when calculating DOF.

--
regards
Karl Günter Wünsch

Nico Westerman · Dec 18, 2004

Sol said:
I agree with you, Dennis. Bokeh is certainly a component of image.
Depending on what the background is doing, even the best of lenses
can create useless bokeh. Bokeh is what the lens does to the OOF
areas. If you are using a high aperture setting, than the DOF is
huge, pretty much leaving no out of focus areas to create bokeh. I
assume when you mentioned your 200/4 at f/16, you are pretty tight
on your subject, as in a macro situation, correct? I did try to
reference to Nico, the factor that regardless of focal length, the
closer you get to the subject the more OOF areas become a factor.
And thus better chance for bokeh. maybe I didn't explain it well
enough. Sorry.

Not at all Sol, you were very clear. And it is a nice thing that a such important point as bokeh is discussed in the forum. Bokeh probably is one of the major aspects of an image that makes the difference between a sharp and well exposed shot and a beautiful touching photo. I am glad to hear your opinion that bokeh is not necessarily restricted to big glass. Nico.

Nico Westerman · Dec 18, 2004

Yes I understand. Foveal multiplication gives a bigger DOF with the same F-stop. So concerning low light photografy you can shoot having the same DOF with a wider diafragm than on 35 mm. Yes thats a good thing. Nico.

Dennis said:
Nico Westerman said:

I understand that with you last remark about the foveal
multiplication factor, you probably mean that you get a less
beautiful bokeh?

Click to expand...

Well, my point was really that, if you currently avoid wide
apertures on 35mm because of too-shallow DOF, you can probably
expand your horizons a little with the 7D, shooting faster and
maintaining the same DOF (and, possibly, same bokeh, depending on
what lens you're using).

Dennis

Why still big glass?

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