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210 AF IF or 300 APO AF IF for beauty work

fotografz

Well-known member
I'm been kicked out of forums for trying to explain this to nonbelievers. Some people just don't get it. :loco:

But everything out of focus will look very different, and the background will be magnified, making it LOOK more out of focus.
Perhaps an easier way to clarify for non-believers is to reference Motion Photography where you can see it demonstrated all in one framing. The technique of Zooming the background while the subject remains the same size shows that the DOF remains the same.

One of the first to employ this "dolly zoom" was Alfred Hitchcock in the 1940 Gothic mystery "Rebecca" ... his first Hollywood production ... where it was used to an unsettling emotional effect when Rebecca suddenly realizes the answer to the hidden mystery, and the background zooms up behind her while she remains the same size.

This perspective distortion effect was first attributed to second-unit cameraman Irmin Roberts, and was more famously used by Hitchcock in the 1958 film "Vertigo" ... and afterwards also became known as the "Vertigo Effect" for obvious reasons.

:) Marc :)
 

ondebanks

Member
I'm been kicked out of forums for trying to explain this to nonbelievers. Some people just don't get it. :loco:

But everything out of focus will look very different, and the background will be magnified, making it LOOK more out of focus.
Gregory, no doubt you are referring to your tour of duty in the Great DOF War over on photo.net MF forum a few weeks back: http://photo.net/medium-format-photography-forum/00Y2tN?
Thankfully, people like you and I prevailed. :thumbup:

To the OP: you'll never see a better explanation of all the nuances surrounding DOF than this:
http://toothwalker.org/optics/dof.html

You do have the right idea that a longer distance from the subject will increase DOF. But if you counterbalance that by using a longer focal length lens (at the same f-stop) to make the image the same size within the frame, then that increase is exactly neutered, and you're back to where you started. Gregory is right about the background looking more oof with the longer lens, but your concern is not the background, it's the 2nd eye of the subject. The only solutions therefore are:
1) stop down the lens more, or
2) move further back and crop in, or
3) stay where you are, use a shorter focal length lens, and crop in.

Ray
 

Dan Santoso

New member
Thanks guys. I will check with my local dealer next week to see if my DF has front focusing. I suspect the focus is not accurate because most of my fashion's image has the clothes as the sharpest part (full body with 80mm).
 

Jack

Sr. Administrator
Staff member
210 f4 ULD AF and 300 f4.5 APO AF are both excellent lenses. On par the 300 APO is probably a bit better, but not hugely. Note there is some sample variation with the 300's when shot wide open, so be sure to test them to confirm you have a copy you're happy with -- a good one is as laser sharp wide open as it is stopped down.
 

David K

Workshop Member
Just when i thought I had a handle on these concepts I find that maybe I don't. As long as we seem to have some experts in this post... doesn't compression, or foreshortening, or whatever you want to call it come into play in focal length selection. I'm under the impression it does... the images I take with, say the 110/2 Hassy are just about perfect (to my eye) for the OP's shot. I would not have thought that using a 300mm lens from a longer distance could achieve the same "look"... irrespective of DOF considerations. If I'm wrong I'd love to be educated.
 

Jack

Sr. Administrator
Staff member
Compression, which is a component of perspective, comes from shooting position only. The fact you generally are further back to fill the frame with a longer lens compared to a shorter lens, is what leads folks to believe it's focal length based. However, if you shoot a portrait from 10 feet with a 300, then from the same spot take one with a 50 and crop the 50 face ~6x to match the 300's framing, you'll find the results are identical on compression (perspective) and only differ on net detail.
 

Guy Mancuso

Administrator, Instructor
Compression, which is a component of perspective, comes from shooting position only. The fact you generally are further back to fill the frame with a longer lens compared to a shorter lens, is what leads folks to believe it's focal length based. However, if you shoot a portrait from 10 feet with a 300, then from the same spot take one with a 50 and crop the 50 face ~6x to match the 300's framing, you'll find the results are identical on compression (perspective) and only differ on net detail.
Agree but disagree. You are certainly bringing the background in more play with a longer lens as it gives the impression the mountain lets say is right behind you as it compresses the foreground and background. I use a 300 on portraits for this very reason is to suck in the background. Now i may have the technical names wrong but that is compression. Just like shrinking a long nose down with a longer lens.

I used that shot above as that model has a long nose and I had a long talk with her as she continues on as a model how to not show that with her angles. If I had it my way i would have went with a 300mm to compress it even more. I'm going by visual impression here
 

Jack

Sr. Administrator
Staff member
Guy, you will get the exact same amount "compression" if you shoot with your 300 and 55 from the same spot and crop the 55 frame to match the 300's. Try it and you'll see you will have the exact same background positioning as well as the same amount of compression. The only difference will be total file detail.

What is different is that we never do that in practice --- as a practical matter we choose our focal length based on our desired framing from our desired shooting position. Thus we create the general assumption for ourselves that longer lenses compress, when in fact it is ONLY the longer shooting distance that affects compression (as well as all other aspects of perspective).
 

Guy Mancuso

Administrator, Instructor
I do understand what you are saying and this debate has gone on for years. You are correct but we not only chose a lens for focal length but maybe the correct word here is perspective or distortion. Maybe better said a longer lens flattens more given the same framing. Maybe the word I am looking for is distortion
 

johnnykurtz

Member
Both shot with the 150D at F11 on a P40+ . So yes i am a touch further back than you would be with a P65. These also have negative clarity on them . This lens is brittle sharp

Now any closer i would most likely get in some DOF issues. I did shoot these handheld. Focused on her eye and recomposed
Guy,

What lights did you use here, were they the Elinchrom Ranger Quadra set?
 

Guy Mancuso

Administrator, Instructor
No they were the BXRI 500 units. I had three going and one failed so I think both of these are only two lights. Used a small Octa and a 27 inch Deep throat.

I only had 8ft ceilings and was very limited on placement. They are two lights otherwise i would have had a rim light on our right side. But the Quadra's would have worked just as well. Maybe add a stop ISO. My P40+ will do a great ISO 200. These were at ISO 100.

Honestly I would love to dump all the BXRI stuff and go with more Quadra's. I have two setups but would love another.

I'm actually trying to decide what to do on the repair of the BXRI its a 300 dollar main board. New units are around 580 dollars. Dilemma
 

johnnykurtz

Member
I have a similar setup, P1-AF with a P40+.

I Have been using 4 AB B1600's, but need portability now. My focus is on commercial product work and the B1600's managed correctly have worked well. I am thinking of going with two Quadra packs and four lights for the mobility. In your judgment is this a sound path? I have not used the Quadra's and want a user opinion.
 

Guy Mancuso

Administrator, Instructor
Johnny the Quadras are really great for portability no question. The heads are delicate though and you need the elinchrom adapters for the soft boxes. So if your careful it will work out great. Obviously you will be missing great modeling lights although the LED is pretty good just not 150 watts good if you know what I mean. Actually going with 2 packs and 4 heads sounds good but power maybe short . I would go 3 packs and 4 heads if you could. All this will fit in a small roller too which you can airline check easily. I have a combination and that is something worth thinking about since the Skyports work with both is get one or two BXRI and replace modeling with 150 watt units than use Quadra in combination like I do with 2 packs and two heads maybe just get a extra quadra head than. Be cheaper route to take and you have AC and DC power combination.
 
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