Need tips before I go on my 1st solo Photo session

[acearchie]

Well I was speaking from experience with my 50/1.4

at 2m distance you have a depth of 9cm at 1.4, more than enough to cope with unintentional movement. (1.8 has 2cm more depth).

If the model doesn't know not to move deliberately, or the photog is careless, or focus hasn't actually been achieved then all bets are off but the minimal movement from the recompose, no, it won't cause loss of focus.

I have a triangle diagram that disagrees with you!

 

[simonsi]

I have a triangle diagram that disagrees with you!

Lets see it then?

 

[Reality4711]

Cannot Argue

I have a triangle diagram that disagrees with you!

Cannot dispute your figures on the 50mm lens however unless I was using a crop body it would not be my first or second choice for portraiture in general. Some special shots might make it more applicable; close up eyelashes, jewellery or makeup but those apart a longer lens would be favourite IMO.

Subsequently a longer lens+ f1.4/1.8/2.0 and 2.8 would provide much less margin for error and make timing and stability (given the camera lens focuses well) very important indeed.

This is why I suggested the f5.6 setting (with a 100th plus exposure) on a 100mm lens just to get the shot; as you improve your technique.

I remember having to work damned hard when using a rented eos 200mm f1.8 lens on countryside hair fashion shoot where the customer had demanded (sorry requested) an almost impossibly shallow depth of field so that the moving hair would only be in sharp focus as it crossed the models face; which had to be soft:roll eyes:

In the end only a tripod + plus back support for the model enabled the shot. Freezing the hair, seeing the soft facial and and forest background sunlit and way OOF..

I do remember stopping down to f2.8 at a 500th.. I think it was on Portra film.

Anyway, Regards

Sharkey

 

[acearchie]

Lets see it then?

Let's assume we're using a 50/1.4 (not really an exotic lens) on a 35mm camera, resulting in a horizontal angle of view of about 40°. Make the focus distance 2 m, and the focus shift is 12 cm, but the front depth of field is only 6.5 cm. Here the focus shift is almost twice as big as the depth of field.

Using your example of 2m with a 25˙ shift leaves you OOF. Maybe too much angle but I'm only making a point really. Make that angle a more reasonable 15˙ and you're still 7cm away from your plane of focus. Assuming the camera has focused in the middle of the DOF then you are still out!

 

[The Bad Guy]

You're telling this guy (who is new to portraiture) to shoot wide open...and then expect sharp portraits?

Interesting.

 

[simonsi]

Using your example of 2m with a 25˙ shift leaves you OOF. Maybe too much angle but I'm only making a point really. Make that angle a more reasonable 15˙ and you're still 7cm away from your plane of focus. Assuming the camera has focused in the middle of the DOF then you are still out!

Well on an FX camera with a 50mm the FoV is only 40deg in total so your 25deg is physically impossible (you can do it by crossing the centreline of the lens but that would be reducing the error).

Its more reasonable and realistic to take a point 50% away from the centreline, so that would be an angle of 10deg, on a 2m range that would mean a movement of 3cm in the focal plane, which would be within the DoF...which is why the technique works...even on a f/1.4.

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You're telling this guy (who is new to portraiture) to shoot wide open...and then expect sharp portraits?

Interesting.

Nope. Trying to troubleshoot why he had OOF eyes even at f/3.2 after focus-recompose...

 

[Reality4711]

No - but

You're telling this guy (who is new to portraiture) to shoot wide open...and then expect sharp portraits?

Interesting.

No - But I don't think anyone has read my comments or thought them of any use so it's not surprising you think that.

Regards

Sharkey

 

[The Bad Guy]

No - But I don't think anyone has read my comments or thought them of any use so it's not surprising you think that.

Regards

Sharkey

My apologies. I skimmed the thread and just saw 'wide open, wide open, wide open' everywhere.

 

[acearchie]

Well on an FX camera with a 50mm the FoV is only 40deg in total so your 25deg is physically impossible (you can do it by crossing the centreline of the lens but that would be reducing the error).

Its more reasonable and realistic to take a point 50% away from the centreline, so that would be an angle of 10deg, on a 2m range that would mean a movement of 3cm in the focal plane, which would be within the DoF...which is why the technique works...even on a f/1.4.

Sorry, you're completely right. My brain had a mathematical brain fart, unless of course I am the only one that has managed to bend space and time.

I still think that recomposing is a large factor with focus with new shooters.

When shooting 85mm (I seriously love wide open) I make sure to shift with the plane of focus rather than rotate my body and I get much better results!

 

[Reality4711]

When shooting 85mm (I seriously love wide open) I make sure to shift with the plane of focus rather than rotate my body and I get much better results!

Good Point there sir!

Using zee neez to sway across the plain is v good advice indeed. It can be expanded to include other facets of photography. 'Framing with the feet' comes to mind. Kind of points towards the non reliance on technology in creating a good image.

Regards

Sharkey