One Sick Kit Lens (for the money)

Just wanted to add, because my mind is trying to bend around the fact two people talking about the f3.5-f5.6 "better DOF" over the f2.8, that the 17-55mm can STOP to 3.5 and 5.6 for a wider DOF, but still can't grasp how the 18-55mm achieves "BETTER" then f2.8 shallow DOF???

BigAlz1 wrote in post #10960973
So, you are saying the lens is NOT mechanically slower?

So far you're the only person to have mentioned focus speed in this thread.

BigAlz1 wrote in post #10960973
Also, do you really believe that f5.6 has better DOF at 55mm then f2.8? f3.5 better at 18 then f2.8? Both lenses cover the 18-55 sweep, I am still trying to understand how the f3.5-f5.6 has better DOF then the flat f2.8.

The quote was that the kit lens has more (i.e. deeper) DoF because it's slower (i.e. has a smaller minimum aperture). You seem to have confused the word 'more' with the word 'better'.

BigAlz1 wrote in post #10960973
Thanks for the photography lesson, but I am fully aware of aperture and it's relative speed to light.
So, you are saying the lens is NOT mechanically slower? Also, do you really believe that f5.6 has better DOF at 55mm then f2.8? f3.5 better at 18 then f2.8? Both lenses cover the 18-55 sweep, I am still trying to understand how the f3.5-f5.6 has better DOF then the flat f2.8.

I am defiantly ready for that lesson.

Before being defiant read Kitacanon's post again. It is completely accurate, while your response is certainly confusing.
Aperture is not relative to the speed of light: it is the diameter of the hole through where light travels from the outside of the lens outside to the sensor.
Mechanically slow... no one has talked about that.
The 18-55, having a higher f/ stop, has a smaller aperture, which means a deeper depth of field: a longer range will be in focus.
At 50mm f/2.8 and a subject at 6 ft you will have a total of 0.46 ft in focus.
At 50mm f/5.6 and a subject at 6 ft you will have a total of 0.92 ft in focus.
It is easier to get things in focus when you work with small apertures.

BTW the 18-55is kit lens is a great lens.

juanpafer wrote in post #10962627
Before being defiant read Kitacanon's post again.

OP didn't mean "defiantly"...that's spell check's way of correcting "definately" that should be 'DEFINITELY"...I see that all the time in college essays...my cue to those writers is to remember that definitely is finite....and that spell check can't think...it can only guess.

Now back to the subject...more depth of field/focus, is not the same as better, any more than less depth of field is worse...it depends on the purpose of the shot and whether the intent of the shot is achieved.

...and now the definition of "stop"... "stop" refers to F-stop, the aperture...
to stop DOWN is to CLOSE the aperture making it smaller, which creates MORE depth of field/focus
I've not really heard "to stop UP" though...the opposite is to OPEN UP the lens...the aperture.

I've often used used the term open (close) the lens (aperture) a click or two, click referring to a FULL F-stop, even though I know that a click can be thought of as the wheel's "click" and interpreted as either 1/2 or 1/3 of an F-stop depending on the way the EV compensation/ISO is set up in the camera....so I try to refrain from using the word click to refer to a full F-stop (click referring to mechanical aperture rings that click between full F-stops....even though a (very) few lenses 'click' at 1/2 F-stops, and even fewer don't click at all...oh well...

AND...opening/closing "a stop" CAN ALSO refer to the shutter speed rather than the aperture...if you're already 'wide open' at the maximum aperture, then to open 'a stop' will require slowing the shutter speed by 1/2 (which as I mentioned, gives to us the term "SLOW LENS", though light can be such that you may have to slow the shutter speed to open a stop even on a 'fast' F1.4 lens)...

Hope this helps...

p.s. hope you like the revised ice cream crop

OP, if you don't need the fixed aperture, "fast" zoom, then the kit lens is a superb performer. I love shallow DOF photography, so I need "fast" lenses.

Well, BigAl does have the nifty50, at least according to the gear listed (which doesn't show the 18-55is)...so he does have the option to get shallow DoF...

This thread has taken more turns then the Tail of the Dragon (a famous road here in TN that has 11 miles of an insane amount of hairpin turns).

Just want to rebuttal a bit,
Yes, I have a way with words sometimes, aperture speed has everything to do with light. When I said speed relative to light, everything in photography is relative to light.
And I am still blown away that everyone thinks the 18-55 at 5.6 @ 55mm, "has more" DOF then the 17-55 at 5.6 @ 55mm. For the most part (in general) lenses are NOT as sharp wide open then they are stopped down.

The 18-55 is wide open at f5.6 @ 55 where as the 17-55 is 2 stops down at f5.6 which in most cases should make it sharper at the same DOF.

And just one more thing, when I think of MORE DOF I think of the separation of the focused subject to unfocused background, I am also scratching my head on why everyone is calling a smaller aperture "more DOF".

Maybe it's because I didn't go to collage for Photography. Can I not get anyone on my side, I can not be the only one that thinks "more DOF" doesn't mean wider, and that both lenses @ f5.6 (55mm) that the 18-55 is more?

Somebody throw me a bone here, I smell another photography lesson coming but I just hope it explains the same thing I have asked the last three posts including this one.

kitacanon wrote in post #10962908
Well, BigAl does have the nifty50, at least according to the gear listed (which doesn't show the 18-55is)...so he does have the option to get shallow DoF...

I do need to update my lens list thanks

To sum up what I am being asked to except as fact,

More DOF = wider aperture
A lens stopped down 2 steps has less DOF at the same aperture
A lens @ f5.6 has more DOF then a lens at f2.8 at the same focal length

I have a lot to learn because all of those are the complete opposite of what I thought I have learned over the years. I am really starting to question my technical since of photography now.

BigAlz1 wrote in post #10963099
This thread has taken more turns then the Tail of the Dragon (a famous road here in TN that has 11 miles of an insane amount of hairpin turns).

Just want to rebuttal a bit,
Yes, I have a way with words sometimes, aperture speed has everything to do with light. When I said speed relative to light, everything in photography is relative to light.
And I am still blown away that everyone thinks the 18-55 at 5.6 @ 55mm, "has more" DOF then the 17-55 at 5.6 @ 55mm. For the most part (in general) lenses are NOT as sharp wide open then they are stopped down.

The 18-55 is wide open at f5.6 @ 55 where as the 17-55 is 2 stops down at f5.6 which in most cases should make it sharper at the same DOF.

And just one more thing, when I think of MORE DOF I think of the separation of the focused subject to unfocused background, I am also scratching my head on why everyone is calling a smaller aperture "more DOF".

Maybe it's because I didn't go to collage for Photography. Can I not get anyone on my side, I can not be the only one that thinks "more DOF" doesn't mean wider, and that both lenses @ f5.6 (55mm) that the 18-55 is more?

Somebody throw me a bone here, I smell another photography lesson coming but I just hope it explains the same thing I have asked the last three posts including this one.

no lesson here, but I think when people that say "more" DOF, they mean "DEEPER" depth, or more in focus. LESS DOF = shallower, or less in focus.

both lens at the exact same focal length (not just the markings), and same aperture should have the exact same DOF.

You are right, that most lenses are sharper when you stop them down. but it's quite possible at 5.6, the 17-55 and 18-55 have the same sharpness. but if you buy the 17-55, you are not buying it to have it sharp at 5.6, you are buying it to have it sharp at 2.8, 4.0, etc that the kit lens cant do (@55mm).

how did this turn into a dof debate/lesson!!!!!????​? lol

Thanks

ilumo wrote in post #10963228
no lesson here, but I think when people that say "more" DOF, they mean "DEEPER" depth, or more in focus. LESS DOF = shallower, or less in focus.

both lens at the exact same focal length (not just the markings), and same aperture should have the exact same DOF.

You are right, that most lenses are sharper when you stop them down. but it's quite possible at 5.6, the 17-55 and 18-55 have the same sharpness. but if you buy the 17-55, you are not buying it to have it sharp at 5.6, you are buying it to have it sharp at 2.8, 4.0, etc that the kit lens cant do (@55mm).

BigAlz1 wrote in post #10963208
To sum up what I am being asked to except as fact,

More DOF = wider aperture
A lens stopped down 2 steps has less DOF at the same aperture
A lens @ f5.6 has more DOF then a lens at f2.8 at the same focal length

I have a lot to learn because all of those are the complete opposite of what I thought I have learned over the years. I am really starting to question my technical since of photography now.

ACCEPT as fact
More DoF is acquired by using a SMALLER aperture (bigger number on the aperture dial...F8 not F2)
A lens stopped down is making the aperture smaller, hence more DoF (assuming shot from the same distance)
A lens @ 5.6 has more DoF THAN a lens @ F2.8 WHEN THAT LENS IS SET AT 2.8....when the F2.8 lens is set at 5.6 and at the same FL they will have the same DoF...
But...the 18-55 lens that has 5.6 as it's widest aperture @ 50mm will not likely be as sharp as a 50mm lens that has F1.8 as its widest aperture...as most faster/wider aperture lenses will LIKELY be sharper.

I say "likely" because a 1.8 lens is easy to make (requiring less glass) than a 50mm/F1.4 lens and so by F4 they would likely be very VERY close indeed in terms of sharpness...though @ F1.8 the 1.4 lens will LIKELY be sharper, being stopped down an F-stop.

...but both will probably be much sharper than the 18-55 @ 50mm because because it's 5.6 is it's widest aperture using ALL of the glass (edge to edge) to refract the rays of light, whereas the wider aperture models stopped down to 5.6 are using less of the glass's edge.

This is why using a 50mm lens made for a 35mm format camera will often be sharper on a DX/crop sensor than one made the DX/crop sensor...because the edges of the image created by the 35mm format lens will be cropped off the (softer) sides of the CROP/DX sensor, leaving the more of the center, the better part, of the image. This explains why the Nifty50 is so nice on the crop/DX cameras...it was made for the 35mm film format camera...

(The DoF for ALL 50mm lenses will be the same because that's a function of the size of the sensor...)

Kit lens sharper than 17-55?

Riiiiiiiiight... I'll have some of whatever you're smoking...

darosk wrote in post #10963567
Kit lens sharper than 17-55?

Riiiiiiiiight... I'll have some of whatever you're smoking...

at f/8 or f/11 where he was shooting, it is quite possible.