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08-11-2018, 02:43 PM   #31
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QuoteOriginally posted by Rondec Quote
. Yes, it is standing closer to the subject, but assuming you want the same framing and are using the same focal length, you can stand closer to the subject with a larger sensor than with a smaller one.
Well, you seem to know that a larger format doesn't have a narrower DoF than a smaller format, Rondec, but many people think it does, of its own accord.

Aperture, focal length and subject distance are variables, but not sensor size.

To replicate Field of View however (a different thing altogether), the larger format is forced to get very close indeed, and this may not be either practical (the subject says you're invading their personal space) or possible (an 85mm typically has a 90cm minimum focusing distance).





08-11-2018, 03:00 PM - 1 Like   #32
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QuoteOriginally posted by clackers Quote
Aperture, focal length and subject distance are variables, but not sensor size.

To replicate Field of View however (a different thing altogether), the larger format is forced to get very close indeed, and this may not be either practical (the subject says you're invading their personal space) or possible (an 85mm typically has a 90cm minimum focusing distance).
I kind of agree with this, but the problem with that is the change in perspective distortion by getting closer to the subject, so whilst you might achieve the same field of view on full frame by moving closer to the subject, you don't get the same photo (I know you and @Rondec know this - I'm highlighting it for others who might not ).

I hate to do this, but it brings us to the oft-discussed and well-worn topic of equivalence (rolled out here, again, for others' benefit):

When shooting with a 70mm lens at f/2.4 on APS-C, to achieve broadly the same photo on full frame, we'd need to shoot from the same distance using a 105mm (70mm x 1.5) or thereabouts lens at ~f/3.5 (f/2.4 x 1.5). Simply using the same 70mm lens and moving closer will achieve a similar field of view, reduce the depth of field, but mess with the perspective distortion.

I know this is drifting off-topic a bit, but thought it worth re-stating

Last edited by BigMackCam; 08-11-2018 at 03:08 PM.
08-11-2018, 03:06 PM - 1 Like   #33
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QuoteOriginally posted by BigMackCam Quote
I kind of agree with this, but the problem with that is the change in perspective distortion by getting closer to the subject, so whilst you might achieve the same field of view on full frame by moving closer to the subject, you don't get the same photo (I know you and @Rondec know this - I'm highlighting it for others who might not ).

I hate to do this, but it brings us to the oft-discussed and well-worn topic of equivalence (rolled out here, again, for others' benefit):

When shooting with a 70mm lens at f/2.4 on APS-C, to achieve broadly the same photo on full frame, we'd need to shoot from the same distance using a 105mm (70mm x 1.5) lens at ~f/3.5 f/2.4 x 1.5). Simply using the same 70mm lens and moving closer will achieve a similar field of view, reduce the depth of field, but mess with the perspective distortion.

I know this is drifting off-topic a bit, but thought it worth re-stating
Excellent point, Mike.

Bringing a FF camera closer in to replicate an APS-C field of view (and we're talking FoV now rather than DoF) has its cost in perspective, too.

Changing lenses becomes preferable.

08-11-2018, 03:37 PM   #34
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QuoteOriginally posted by clackers Quote
It's a myth, Wasp.

Standing closer to the subject reduces DoF, sensor size doesn't.

No, Larger Sensors Do Not Produce Shallower Depth of Field | Fstoppers
It may be accurate but I am going to laugh at the fact you quoted F-Stoppers Ian! After the things you have said about them!

08-11-2018, 05:04 PM - 1 Like   #35
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QuoteOriginally posted by SSGGeezer Quote
It may be accurate but I am going to laugh at the fact you quoted F-Stoppers Ian! After the things you have said about them!
They're pretty empty-headed, mate, to be sure.

Don't get me started about DPR!

08-11-2018, 05:20 PM - 1 Like   #36
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QuoteOriginally posted by clackers Quote
It's a myth, Wasp.

Standing closer to the subject reduces DoF, sensor size doesn't.

No, Larger Sensors Do Not Produce Shallower Depth of Field | Fstoppers
I was going to say, use a 35 at 2.8 and get close to your subject. I used to have my students do creamy bokeh shots with point and shoots and 50 ƒ2s , by getting close and shooting in the school atrium a long way from the back ground. Start with what you have, learn to get a smooth creamy background, then decide if you need super fast glass. For my use, I wouldn't buy 1.4 glass for that reason, because portraits with really narrow DoF usually suck. I buy 1.4 glass for shooting in dark places. But if you are determines to start with wider aperture, try the 50 1.8 first, see if you like it. You probably won't want to shoot less than ƒ2 in any case, and ƒ4 or 5.6 is more likely. It's all about taking charge of the background.
08-11-2018, 05:39 PM   #37
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QuoteOriginally posted by normhead Quote
I was going to say, use a 35 at 2.8 and get close to your subject.
Yep, good method.

Standard 24-70 will do this, no need for an exotic prime.



08-12-2018, 03:01 PM   #38
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QuoteOriginally posted by clackers Quote
It's a myth, Wasp.

Standing closer to the subject reduces DoF, sensor size doesn't.

No, Larger Sensors Do Not Produce Shallower Depth of Field | Fstoppers
It's all about reproduction ratio.

08-16-2018, 04:57 AM   #39
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QuoteOriginally posted by normhead Quote
, because portraits with really narrow DoF usually suck.
Wrong. I use long lences fa135 & da 200. All cluttering background are in a creamy dreamy paste of colors
08-16-2018, 05:58 AM - 1 Like   #40
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That was from FA135mm which can focus real fast and right on all the time





This was from DA200mm at f:3.2

Last edited by danielchtong; 08-16-2018 at 06:06 AM.
08-16-2018, 07:01 AM   #41
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QuoteOriginally posted by danielchtong Quote
That was from FA135mm which can focus real fast and right on all the time
gorgeous natural colors
08-16-2018, 07:34 AM   #42
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QuoteOriginally posted by danielchtong Quote
Wrong. I use long lences fa135 & da 200. All cluttering background are in a creamy dreamy paste of colors
You do know that by narrow DoF I was discussing the famous "one eye in focus" thing. You have a nice creamy background but you also have the whole subject in focus.

The narrow DoF comment was for the face only partially in fectus thing.

Sheeeh do I have to explain everything?

IMHO a better photographic practice for portraits is to control your back ground and shoot for the necessary DoF, just so you don't have to cream out your background.

And your 200 3.2 image I probably would have gone at least 4, maybe 5.6. You don't provide EXIF but my guess is the 135 image is not the widest possible aperture. But ya, that is one of my favourite photographer tricks, use long lenses to provide the necessary background blur.

Last edited by normhead; 08-16-2018 at 07:39 AM.
08-16-2018, 03:57 PM   #43
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QuoteOriginally posted by normhead Quote
You don't provide EXIF but my guess is the 135 image is not the widest possible aperture. But ya, that is one of my favourite photographer tricks, use long lenses to provide the necessary background blur.
Again it is wrong. The FA135mm was at F:3.5 . It is still wide and there was no need as I had the background (ugly wall character)blurred out.

Image2.jpg photo - Daniel TONG photos at pbase.com

BTW we (at least it is me) want the subject to stand out (the subject's eye or eyes ). The rest to me is not relevant at all.
08-18-2018, 01:15 AM   #44
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QuoteOriginally posted by normhead Quote
IMHO a better photographic practice for portraits is to control your back ground and shoot for the necessary DoF, just so you don't have to cream out your background.
are you sure you got it right this time? ;-)

I see your point.. choosing background more carefully allows you to use whatever f stop one needs/wants..
Actually, looking at some of my pics, i have done that (albeit a bit unconsciously..)
08-18-2018, 02:11 AM   #45
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QuoteOriginally posted by normhead Quote
And your 200 3.2 image I probably would have gone at least 4, maybe 5.6. .
For da200 , using f:4 or 5.6 is like asking for trouble. That is your image though.
You will end up busy cloning out all the blemishes or pimples.......
No portrait subject (women) like that LOL
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