f/2.8 with IS --- vs --- f/4 with IS

[coachboz68]

I'm going to ask an imperfect question, so bear with me, but I think it will lead to the answers I am looking for.  Iv'e started a new thread but this topic arises in many other threads in different bits and pieces. 

Let's take a lense like the EF 16-35 where we have the choice of f/4 with IS that (I believe) is rated at something like 4 Stops, and the f/2.8 with no IS. 

Let's further assume that I'm going to do walk-around city/street shooting where I will most frequently shooting WITHOUT a tripod. 

While the 2.8 affords me faster shutter speeds, I am afraid that the shallow DOF will be undesirable in many shots.  Therefore, for mostly handheld shooting where shallow DOF is not desireable, would one be better off with the IS with a min of f/4 given shutter speed (for these kinds of pics) is not the major concern?  

I know there are a lot of variables still left unexplored, so the answer will likely still be "it depends" but hopefully this the above scenario is enough to help me start understanding the real-life tradeoffs between a smaller aperture with IS vs a larger aperture without.  

Thanks

[RobertTheFat]

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@ebiggs1 wrote:

Coach,

I've very comfortable with my 70-200 f/2.8 and my 24-70 f/2.8.

One more good reason to go with the f2.8 version is you already have a couple f2.8 lenses.  I think it works out better if the lens stable is, well, stable.  Make sense, all three lenses are f2.8 so there is no worry about switching when you are in an important shoot.  Will this lens work?  It will if the others did sorta thing.

You do need to learn more about DOF as it is not that shallow at 16mm on a 1DX.  Think of this, my friend, if you don't need f2.8 and you own the f2.8 version, you don't need to use it.  It has f4 just like the other one but if you need f2.8 and don't have it available, you are screwed. Do you want to give that fact up for IS that may be of little value anyway on a WA zoom?

No, no way, not never!

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To add to Ernie's point, note that modern autofocus lenses do their focusing at their widest aperture, which improves speed and accuracy. So you may be making good use of the wider aperture, even when you think you're not.

[coachboz68]

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@RobertTheFat wrote:

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@ebiggs1 wrote:

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To add to Ernie's point, note that modern autofocus lenses do their focusing at their widest aperture, which improves speed and accuracy. So you may be making good use of the wider aperture, even when you think you're not.

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No kidding... feels like I never stop learning, which is why I love this as a serious hobby.  Nice little nugget.  

[coachboz68]

Super helpful. Thanks.

[coachboz68]

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@ebiggs1 wrote:

You do need to learn more about DOF as it is not that shallow at 16mm on a 1DX.  Think of this, my friend, if you don't need f2.8 and you own the f2.8 version, you don't need to use it.  It has f4 just like the other one but if you need f2.8 and don't have it available, you are screwed. Do you want to give that fact up for IS that may be of little value anyway on a WA zoom?

No, no way, not never!

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This thread is giving me the exact info for which I hoped.  I think my attraction to the IS was coming from a scenario that seems very unlikely, which would be needing a narrower aperture for DOF and not having enough light for a faster shutter speed, hence wanting the IS to help me with the clear image.  But after realzing that especialy with a wide angle lense, DOF is going to be way less of an issue, then (assuming one can afford the extra cost) the 2.8 is the better approach, all things considered.  

Also, regarding hyperfocal length, from sports shooting I have learned to intuit the general scenarios where my DOF is going to be shallow or deep, (but honestly that matters so much less than getting the great action shot).  I will start learning more about the mathematical calculations to determine it vs just gut as that will help me with the types of shooting I am starting to explore.  Thanks everyone! 

[Waddizzle]

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@coachboz68 wrote:

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@ebiggs1 wrote:

You do need to learn more about DOF as it is not that shallow at 16mm on a 1DX.  Think of this, my friend, if you don't need f2.8 and you own the f2.8 version, you don't need to use it.  It has f4 just like the other one but if you need f2.8 and don't have it available, you are screwed. Do you want to give that fact up for IS that may be of little value anyway on a WA zoom?

No, no way, not never!

---

This thread is giving me the exact info for which I hoped.  I think my attraction to the IS was coming from a scenario that seems very unlikely, which would be needing a narrower aperture for DOF and not having enough light for a faster shutter speed, hence wanting the IS to help me with the clear image.  But after realzing that especialy with a wide angle lense, DOF is going to be way less of an issue, then (assuming one can afford the extra cost) the 2.8 is the better approach, all things considered.  

Also, regarding hyperfocal length, from sports shooting I have learned to intuit the general scenarios where my DOF is going to be shallow or deep, (but honestly that matters so much less than getting the great action shot).  I will start learning more about the mathematical calculations to determine it vs just gut as that will help me with the types of shooting I am starting to explore.  Thanks everyone! 

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DOF?  Take a look at the tool at the link that I posted.

[coachboz68]

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@Waddizzle

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DOF?  Take a look at the tool at the link that I posted.

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Waddizzle... already printed out a few pages for my lenses and common zooms.  Thanks! 

[coachboz68]

Just downloaded an app for my Android phone called HyperFocal Pro.  Simple, straightforward, exactly what I need.  

As an aside, back to my original hypothetical with the 16-35... for my IDX II, when I play with some inputs, I see that 16mm @ f/2.8 has a hyperfocal distance of only 10.3 ft.  Looking at other numbers, the DOF is much larger than I suspected at that lens length. 

Fantastic info in this thread.  Thanks again to all.  This has been hugely helpful.  

[ebiggs1]

"Waddizzle... already printed out a few pages for my lenses and common zooms."

I have no idea what this suggestion was but experience is way better that picking up a chart evey time you want to know something.  Especially as DOF.  Its OK to check one out to get the general idea I suppose but as you get more experience you won't need it.  Go out and shoot some stuff.  Just anything and edit it.  Study what you did.  Like I say way better than a chart.

BTW, are you going to carry a ruler or tape measure along, too?

[coachboz68]

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@ebiggs1 wrote:

"Waddizzle... already printed out a few pages for my lenses and common zooms."

I have no idea what this suggestion was but experience is way better that picking up a chart evey time you want to know something.  Especially as DOF.  Its OK to check one out to get the general idea I suppose but as you get more experience you won't need it.  Go out and shoot some stuff.  Just anything and edit it.  Study what you did.  Like I say way better than a chart.

BTW, are you going to carry a ruler or tape measure along, too?

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I switched to an app, so I don't have to print the paper. 🙂   For my learning style, it will augment my field experience.  I remember things better when I know the "why" behind the "what" and this helps me do that.  And I find the math interesting.  Just the way I'm wired.  

No tape measure, but from a life spent in football, I can call out distances in yards more accurate than the average bear, at least within 100yards. 🙂 

[ebiggs1]

"I can call out distances in yards feet more accurate than the average bear ..."

I knew you could and it is the best way to go.  Let the chart readers read their charts while you make photographs!