Back to fully manual - some focus questions...

[GIlesM]

I recently purchased a 12mm Samyang fully manual lense.

The lense if 12mm f2.0-f22.

This is a fantastic addition to my collection and has really opened up eyes, not only to the types of photography now available to me, but to how much 'basic' photography skills I have never had to think about due to the automatic nature of modern cameras. How much I had forgotten? too much, way too much.
My first SLR was fully manual (a "Zenit") I think? I was around 17 and had a three week photography section in my art class at school.
For a few years I used the manual camera, but then I upgraded to Minolta 7000 Dynax. My first fully automatic DSLR. I soon got lazy and set it on full auto. I still have that Minolta and lenses.

I have been using full auto ever since. To suddenly dive back to the world of fully manual this week has been a shocker! I think I have got it all back now, but have some questions please.

If I set my Samyang at the 3ft focal length, with f22, all from 3ft and beyond to infinity is nice and sharp. As I select lower f-stops objects at 3ft stay in focus, while the background, all beyond 3ft, starts to lose focus.

Am I right up to this point?

If I select the infinity point on the lense and f22 all is in focus, but infinity plus f2 and objects 3 feet away are out of focus, and infinity is sharp.
Changing f-stops down from from f22 to f2, loses focus on objects at 3 feet, whilst maintaining focus on infinity.

Am I right up to this point?

If so, and here is the question, If I set to infinity, at what distance does constant focus start across all f-stops? it looks to be at around 6-7 feet, could that be correct?
(the focal scale on the lense starts at .66 feet and ends at 3 feet, then there is a a gap in markings between 3ft and the infinity marking line.)

So, if I go out shooting street scenes, set to infinity, I am free to select any f-stop, or just leave it at f2, and everything beyond say 6 feet, would be in focus? To put it another way what is the closest distance that "infinity" starts at?

I am tempted to set up as follows, infinity plus f5.6, I can't decide what is best, so hence the question.

Should I set to infinity plus f5.6 or infinity and select the f-stop as required to bring me to a minimum shutter speed of 1/500 ?

As an experience, going back to fully manual has something to offer as it forces you remember, or indeed learn for the first time, basic principals.
I would say it is not for everyone, but useful if you really want to know just what your camera is doing when you set it to fully auto.

Is there any one "set and forget" point on this lense? I am thinking perhaps not, as that is the whole point of a manual lense.

 

[john.margetts]

The standard advice has always been 'F/8 and be there' and that will work pretty well with your 12mm lens.

12mm seems pretty wide angle for street work - you will need to be nearly touching people to avoid the street looking empty.

 

[GIlesM]

John, so, f8, but what focus point 3ft or infinity? If I set to f8 and 3ft, will all at 3ft and beyond be in focus?
Yes, it is wide, but I am experimenting between this and a 50mm f1.8 Prime lense, the standard kit (16-50) or my 55-210 mm f4.5-6.3 zoom.
The lense was primarily purchased for astro, landscape and building interiors, street work will be an experiment.
Perhaps the 12 mm will provide a study of people in their environment, rather than the close in 50 mm.
I wish I could use all 3 at once!

 

[john.margetts]

F/8 on a 12mm lens - ideally focus on the hyperfocal distance but I would focus on 10 feet and not care about infinity.

 

[GIlesM]

ok, but my lense has no marking for 10ft, so I am popping out right now down to the docks, to give my lense it's first outing in the real world!
Thanks for the help, I will report back later....

 

[GIlesM]

The new lens worked out much better than I could even have wished for, I am very happy. Focus was not an issue, my camera was able to give a good indication as to what was in focus, so I used manual focus with a mix of f22, f8 and f5.6.
Loving the wide angle, it really changes my photographic opportunities, all good, thank you.
As you said, this is not the lens for street photo's of people, but for vistas, and buildings, capturing entire scenes, fantastic.
Pretty nice photo's of my wife having a drink at a cafe, not much distortion, but captured the whole scene, much better than 55mm, 35mm or even 16mm. Happy.

 

[GIlesM]

here is a shot of a pig.

 

[dxqcanada]

Depth of Field Table

 

[GIlesM]

Nice one dxqcanada, shame my Sony a6000 is not listed

 

[dxqcanada]

Just go with any NEX ... same sensor size.

 

[GIlesM]

Ohh, I see, thank you!

 

[GIlesM]

Great! Thanks, now I know the hyperfocal per f stop, I can understand why my shots worked out yesterday.
I did it right but just by instinct and luck, now I have the weapons to suceed!

 

[KmH]

. . . If I set my Samyang at the 3ft focal length . . .

The focal length of the lens is 12 mm. What you describe is the point of focus distance.

 

[GIlesM]

. . . If I set my Samyang at the 3ft focal length . . .

The focal length of the lens is 12 mm. What you describe is the point of focus distance.

Keith, thank you for the correction, much appreciated.

 

[jcwphoto]

Depth of Field is a combination of focal length, aperture and distance from subject. For instance you can shoot with a macro lens at F 22 from an inch away and have a very shallow depth of field. It takes time and practice. I didn't make this video but I show it too my students.