How to use a manual focus ultra wide angle lens

[lauren123]

Dear All,

I wonder if anyone can enlighten me on how to use an ultra wide lens, Sanyang 14mm, f2.8 to be precise. It's not that I am being lazy and popping out questions without doing my homework. I have done some research, despite there are a few "solutions" available on the internet,  the terminology and methods are still beyond my knowledge. I am still clueless.....

With my come-with-the-camera Canon 18--55mm lens, I can manually focus with no problem, it's all very straight forward. But with this Samyang lens, it's another story,  I really hope someone can explain to me that how I can take sharp pictures with this lens.

P.S: One method I've found on the internet is to mark and remember this:

With a 14mm lens

F4 Focal point1.65m  0.8m--infinity will do
F8 Focal point0.8m  0.4m--infinity will be OK
F16 Focal point0.4m  0.2m--infinity will be fine

I tried, but 1) I don't 100% understand what this means, 2) I guessed what he meant and tried with my camera, doesn't work, photo is still blurry ......


Are there any other practical tips (in simple language please)?

Thank you!!!!

[Rhossydd]

First question; Have you managed to take any sharp pictures with the lens at all, at any focus position or f stop ?

I ask this as the quality control on the Samyang 14mm has been poor at times and there are a few copies that are either completely faulty or more often have a poor calibrated focus scale.
Focussing the 14mm will be easier when it is set to f2.8 as there's less depth of field, then stop down to the desired f stop after focussing to take the picture.

I'm guessing you've an APS-C camera, rather than a full frame sensor model ? Unfortunately that means you'll probably have a worse viewfinder image to focus with, so try using live view with the rear screen. It's a bit slow to work with, but you should be able to use it to help check your lens isn't a bad example.

They can be great lens, I've got one myself, so stick with it.

[Iluvmycam]

You zone focus, you measure the distance or you focus with a EVF or screen.

[BobShaw]

Hi Lauren,
Will do, OK and fine are not terms that you want to aspire to. There is a lot of rubbish on the Internet.

Depth of field is a myth. There is only what distance that is in focus, anything else is just "acceptably in focus", meaning close. They say "acceptably in focus", but acceptable to whom is what you need to decide.

The distance quoted are probably from a hyperfocal app.

My system is look through the viewfinder and get what you want in focus. As others have said, a bigger camera makes that easier.

Also if it's all blurry, is it focus or other problems like lens quality, weak tripod or slow shutter if hand held?

[Rhossydd]

Depth of field is a myth.

It's NOT a 'myth', depth of field is the standard term used in photography to describe the range of distance that objects look acceptably sharp.

This is the beginners question section where just using the basic standard language of photography without pedantic definition and qualification is more helpful to those trying to find their way in the subject.

[PhotoEcosse]

This is the beginners question section where just using the basic standard language of photography without pedantic definition and qualification is more helpful to those trying to find their way in the subject.

Well said.

Lauren,

With that lens, it should be difficult to get anything out of focus without really trying to do so.

I suspect that there is either a fault in your lens or, as suggested above, the blurry photographs are the result of something other than focus problems. However, at such short focal lengths, even camera shake has to be pretty severe to make a photograph very blurry. If you are taking sharp photographs with your kit lens, then I would suspect your Sanyang may be faulty.

[Rhossydd]

With that lens, it should be difficult to get anything out of focus without really trying to do so.

As the owner of one of these particular lenses I can assure you it's actually easier to mis-focus than you might expect. Even on my 5Dii with a specialist focusing screen fitted I usually rely on the AF confirmation system to ensure best focus, but that needs DIY fitting and isn't an option for those without the technical skills to fit and configure it correctly.
They can focus VERY close (275mm), at that distance depth of field is actually relatively small (my phone app says 6cm for a full frame sensor only 4m for an APS-C one both at f2.8 ). Even at 2m subject distance, things beyond 13m won't be sharp. If you put that into the issue of an incorrectly calibrated focussing scale that some examples have suffered, you can see why focussing them isn't always as straight forward as you might expect.
The added complication is that though the small, dim viewfinder of an APS-C DSLR with their screens designed for AF, rather than manual focussing, they're almost impossible to focus accurately by eye. Hence why I suggested live view.

Whilst it's a fantastic lens when used well, and you've good a good example, you don't get anything for free and it requires some care in use to ensure you get the best results possible.

[Telecaster]

Here's the first thing I'd do: set the lens' focus distance to 1 meter, then use a meter stick to position yourself a meter away from, and perpendicular to, a flat subject…a good ol' brick wall will do fine. (Set the focus distance to 3 feet if using a yard stick instead.) Take a photo with the lens at f/2.8. How sharp does the center of the photo look (don't worry about the corners at this point)? Then stop down the lens to f/4, 5.6, 8, 11, 16 & 22, taking a photo at each aperture setting. How do the photos look? Do they get sharper as you stop down, then soften again by f/22 (or maybe even by f/16)?

Report back with your findings. Also, what camera are you using?

-Dave-

[ErikKaffehr]

Hi,

I don't think that I would trust the focusing scale of that lens. I would also be skeptical of DoF tables, they were intended for film days. They may be OK for small prints but definitively not for pixel peeping at actual pixels.

What I would consider is possible that your lens doesn't focus at infinity, which would be a fault with that lens. Say that you look at a bookshelf at 1m using live view. Can you see the titles snap into and out of focus when you rotate the ring? Than you can focus at 1m, now move back to 6 m and try again, can you achieve the image popping into and out of focus?

Best regards
Erik

Dear All,

I wonder if anyone can enlighten me on how to use an ultra wide lens, Sanyang 14mm, f2.8 to be precise. It's not that I am being lazy and popping out questions without doing my homework. I have done some research, despite there are a few "solutions" available on the internet,  the terminology and methods are still beyond my knowledge. I am still clueless.....

With my come-with-the-camera Canon 18--55mm lens, I can manually focus with no problem, it's all very straight forward. But with this Samyang lens, it's another story,  I really hope someone can explain to me that how I can take sharp pictures with this lens.

P.S: One method I've found on the internet is to mark and remember this:

With a 14mm lens

F4 Focal point1.65m  0.8m--infinity will do
F8 Focal point0.8m  0.4m--infinity will be OK
F16 Focal point0.4m  0.2m--infinity will be fine

I tried, but 1) I don't 100% understand what this means, 2) I guessed what he meant and tried with my camera, doesn't work, photo is still blurry ......


Are there any other practical tips (in simple language please)?

Thank you!!!!

[Paul2660]

Most definitely do not trust the focusing scale on the 14mm Rockin/Bowe/Samy.  It's way off, and pretty useless.  There are places you can go and purchase replacement scales you an place over the one on the lens after you have visually calibrated it.

Ton of good advice on this on.

I fully agree with the manual approach, with a static subject. 

The 14mm Samyang, has a huge amount of play in the focus ring, compared to any other lens, ie. lots of turning to get anywhere.

The best way I know of is using Live View to focus as many others have mentioned.  Liveview on Canon is excellent and you can zoom in to 100% and really see what is in or out of focus.  Once that's done, take a visual on where your distance scale is. 

This lens has a huge hyperfocal range, so unless you are doing macro, once you figure out where infinity is at say F5.6 to F8, you will have most of your images in tack focus. 

After all this testing, you still might just have  a bad lens.  Their QA is not the best.  I went through 2 others before I got one that focused evenly.  But also don't despair  as this is an amazing optic for the price. 

Paul

[BobShaw]

depth of field is the standard term used in photography to describe the range of distance that objects look acceptably sharp.

This is the beginners question section where just using the basic standard language of photography without pedantic definition and qualification is more helpful to those trying to find their way in the subject.

Eh, if you actually look "acceptable in focus" is exactly what I said. That there is actually only one distance in focus is a fact.

I think my advice to aspire to get it right and look through the viewfinder and focus is pretty elementary, as was the clarification of "blurry", and a lot more helpful than introducing new terms or "guessing".

I have taken photos for 40 plus years without a depth of field app, but thanks for your help. If people offered their own opinion without trying to ridicule others then that would be nice. Cheers.

[Rhossydd]

The 14mm Samyang, has a huge amount of play in the focus ring, compared to any other lens, ie. lots of turning to get anywhere.

Let's be careful about this. I've never read of any 'play' in the focussing action of these lenses before (ie mechanical slack on the focussing ring when it would need to be turned before moving any optical elements). If there was free play(slack) that would be a mechanical fault that should be returned under warranty.

The lens does turn(about 280deg) a very long way between infinity and minimum focus. Going from infinity to ten feet only requires a short rotation of about 25deg, a further 50 deg cover ten feet to three, so more than half turn covers the range from 3ft to 9 inches. It makes an amount of sense given the depth of field characteristics of the lens, but it's rather unusual handful to focus.

[Rhossydd]

I think my advice to aspire to get it right and look through the viewfinder and focus is pretty elementary,

Elementary possibly, but in the case of this particular lens on an APS-C body not very helpful for the reasons stated above.

[Paul2660]

Let's be careful about this. I've never read of any 'play' in the focussing action of these lenses before (ie mechanical slack on the focussing ring when it would need to be turned before moving any optical elements). If there was free play(slack) that would be a mechanical fault that should be returned under warranty.

The lens does turn(about 280deg) a very long way between infinity and minimum focus. Going from infinity to ten feet only requires a short rotation of about 25deg, a further 50 deg cover ten feet to three, so more than half turn covers the range from 3ft to 9 inches. It makes an amount of sense given the depth of field characteristics of the lens, but it's rather unusual handful to focus.

Your description is better. I was referring to the large amount of rotation between infinity and min focus.

Paul

[NancyP]

I use this lens primarily for landscapes and astrolandscapes and use it on tripod, so it is natural to check focus on Live View with magnification. Focusing ultra-wide-angle manual focus lenses through the viewfinder is hopeless due to the not-very-suitable focusing screens that come standard on the cameras. The distance markings on the Samyang lenses are not 100% correct nor do the lenses have hard-stop-at-infinity focus, so one has to use Live view for critical focus on stars, etc. Depth of field is great, though, so for shooting action, where you don't need tack-sharp infinity, you should "zone focus" (plan on having your subject pass within a plane of acceptable focus). This may require you to recalibrate those less-accurate distance markings inked on the barrel of the lens -  or, just live-view-magnification focus on an object in the plane where the subject will be passing through later.