Problem focussing Samyang 85mm F1.4

**othar** · 07-30-2021, 12:44 AM

Originally posted by Ishpuini

IMHO, the only reliable way is LiveView indeed. Even with the much improved OVF in the K-3III I'm having trouble focusing some of my manual lenses, esp wide open. For most I more or less know the stopped down aperture where increased depth-of-field starts to cover for the missed focus sufficiently. Of course that means the ability to focus manually thourgh the OVF is related to the focal length. The Samyang 16/2 will be OK wide open, the Samyang 24/1.4 needs to be stopped down to at least f/2.8, on the Pentax K50/1.2 it's f/4, etc... For a 85mm lens, I imagine even f/8 might be hard pressed. I know I always use LiveView on my Samyang 135/2.

The longer the focal length, the easier it gets to focus via the OVF in my experience.
If you use PDAF, for focus comfirmation, it should also be accurate for apertures of f2.8 or smaller (the weakness of PDAF is, that you can't do focus calibration for MF lenses individually though, so this might be no option for certain lenses)

pschlute · 07-30-2021, 03:30 AM

Originally posted by othar

the weakness of PDAF is, that you can't do focus calibration for MF lenses individually though, so this might be no option for certain lenses

This should not be a problem generally. Most situations where PDAF confirmation is not working well for MF lenses, are due to the AF sensor being out of tolerance. A global adjustment in the AF-FA menu using the APPLY ALL setting should work well for all MF lenses....it does for me.

If you have a fast MF lens that suffers from "focus shift" you may not get optimum results using this method, and as you note, you cannot make an individual adjustment for that one lens.

Wasp · 07-30-2021, 12:31 PM - **1 Like**

When you get it right, the thin depth of field yields great results - Samyang 85mm f/1.4 on Samsung NX100 at f/2. Much easier to focus with a live view screen than with a mirror and a prism.

**davidreilly3207** · 07-30-2021, 06:48 PM

Originally posted by othar

Why not, I get accurate focus afterwards?

Not sure what your question is. If the diopter is adjusted using the info area text you will get an accurate focus of the subject matter.

wadge22 · 07-30-2021, 09:59 PM

Originally posted by othar

Why not, I get accurate focus afterwards?

I think you don't want to do it that way because that relies on the lens being focused correctly on the screen (which itself must be shimmed right) AND the diopter then correcting focus on that image. If the subject isn't focused on the focusing screen, no adjustment of the diopter will be right, and possibly the wrong one will make the image look best to you.

The info area (or the black guide lines, which I tend to use) doesn't have that problem, it stays right where it is so you can set your diopter correctly on that every time.

Originally posted by othar

The longer the focal length, the easier it gets to focus via the OVF in my experience.

Are you sure? I thought it was the opposite.
It's quite possible that differences in the distance to the subject for whatever is commonly shot with those lenses makes it hard to say.
Again messing around with a DOF calculator may be useful, although now you have me questioning myself even after consulting it.

Have you tried a manual focus 300mm f2.8? By your guidelines, that should be a cakewalk even wide open...
Also don't street shooters generally choose something in the short to normal range largely because of focusing advantages?

Anyone able to clarify?

P.S. I'm not trying to pick on you. Just trying to understand it myself.

**othar** · 07-31-2021, 01:10 AM

Originally posted by wadge22

I think you don't want to do it that way because that relies on the lens being focused correctly on the screen (which itself must be shimmed right) AND the diopter then correcting focus on that image. If the subject isn't focused on the focusing screen, no adjustment of the diopter will be right, and possibly the wrong one will make the image look best to you.The info area (or the black guide lines, which I tend to use) doesn't have that problem, it stays right where it is so you can set your diopter correctly on that every time.

My first step is focusing the lens via Live View, then I adjust the diopter so I see the same area sharp. How should the focus differ afterwards?

Originally posted by wadge22

Are you sure? I thought it was the opposite.It's quite possible that differences in the distance to the subject for whatever is commonly shot with those lenses makes it hard to say.Again messing around with a DOF calculator may be useful, although now you have me questioning myself even after consulting it.

The problem is, the wider the lens, the more surroundings are in the frame -> the smaller the borders between in-focus and out-of-focus areas appear in the viewfinder and it gets harder to pinpoint the exact area in focus.

Originally posted by wadge22

Have you tried a manual focus 300mm f2.8? By your guidelines, that should be a cakewalk even wide open...

I don't own a tele lens that fast, but focusing my Tokina 400mm f5.6 lens is a piece of cake opposed to my Samyang 35mm f1.4 lens. Another aspect to take in mind is: the longer the lens the greater your subject isolation -> you don't need to use apertures as fast as with wide or normal lenses to achieve a good separation from the background.

Originally posted by wadge22

Also don't street shooters generally choose something in the short to normal range largely because of focusing advantages?

In my opinion: no.
The problem of too long lenses for street photography is that you don't get enough information of the surrounding area in the frame. You usually want to show what people are doing or where they are going, to give the viewer some context. With tele lenses you might get good headshots, which can look good depending on how expressive the face is, but if you are just interested in the faces you typically do portraits in a studio where you can also controll the light.
Another problem of tele lenses for street photography is, that you have to back up a great deal to get an interesting framing and for small alleys or side streets there is often not the space to do so.
With long lenses you also create a somewhat voyeuristic vibe, both for the people you photograph and for the people looking at the final image because of the compression and rendering tele lenses introduce to the image.

**brightseal** · 07-31-2021, 12:26 PM

Originally posted by othar

My first step is focusing the lens via Live View

Do you then turn off live view and use the viewfinder or keep it in live view?

**othar** · 07-31-2021, 12:39 PM

Originally posted by brightseal

Do you then turn off live view and use the viewfinder or keep it in live view?

Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise

**brightseal** · 07-31-2021, 01:15 PM

Originally posted by othar

Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise

What I meant was, after you make the adjustments do you still use LV. Are you making the adjustments once or for every pic.

**othar** · 07-31-2021, 02:39 PM - **1 Like**

Originally posted by brightseal

What I meant was, after you make the adjustments do you still use LV. Are you making the adjustments once or for every pic.

Once per day, after that I don't need LV anymore (with the exception of when the camera is on a tripod, then I use LV of course)

Wasp · 08-01-2021, 04:51 AM

Originally posted by othar

Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise

Interesting approach, no problem with it.

Except when you wear multifocal prescription glasses because the diopter that your eyes need depends on the distance that you are focusing at. The corrections for close up (0.5m), medium distance (about 3-5m) and infinity differs This means that for me, the diopter correction in the viewfinder is of little use. Besides, it also means that I have to take my glasses off to shoot and then put them back on to view the rear screen.

**UncleVanya** · 08-01-2021, 06:28 AM - **1 Like**

Originally posted by Wasp

Interesting approach, no problem with it.

Except when you wear multifocal prescription glasses because the diopter that your eyes need depends on the distance that you are focusing at. The corrections for close up (0.5m), medium distance (about 3-5m) and infinity differs This means that for me, the diopter correction in the viewfinder is of little use. Besides, it also means that I have to take my glasses off to shoot and then put them back on to view the rear screen.

That’s odd. I wear that type of glasses and haven’t found that an issue at all for using the viewfinder. I have a massive astigmatism and a large diopter requirement so taking off my glasses isn’t an option. I simply look through them and adjust based on the info below the screen, I don’t recall any issues.

pschlute · 08-01-2021, 07:06 AM

Originally posted by UncleVanya

That’s odd. I wear that type of glasses and haven’t found that an issue at all for using the viewfinder. I have a massive astigmatism and a large diopter requirement so taking off my glasses isn’t an option. I simply look through them and adjust based on the info below the screen, I don’t recall any issues.

I find that odd too.

I use my distance glasses when taking pictures. Setting the dioptre for me is done without a lens. Just concentrate on the grid lines or info display and get them sharp. The point of dioptre adjustment is to dial in the right "prescription" so that you can see the focus screen clearly. The distance of your subject when taking a picture is irrelevant.....it is the lens that produces a sharp image on the screen, not your specs or dioptre adjustment.

Zafar Iqbal · 08-02-2021, 09:14 PM

Had this lens and found it to be really hard to use (portraits). I had changed to a better focusing screen and also used Live View a lot.

The focusing ring being hard and very sensitive didn't help.

Honestly, I don't miss it.

07-31-2021, 01:15 PM	#39
brightseal Site Supporter Join Date: Dec 2015 Photos: Albums Posts: 629	Originally posted by othar Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise What I meant was, after you make the adjustments do you still use LV. Are you making the adjustments once or for every pic. Last edited by brightseal; 07-31-2021 at 01:20 PM.

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07-30-2021, 12:44 AM	#31
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	Originally posted by Ishpuini IMHO, the only reliable way is LiveView indeed. Even with the much improved OVF in the K-3III I'm having trouble focusing some of my manual lenses, esp wide open. For most I more or less know the stopped down aperture where increased depth-of-field starts to cover for the missed focus sufficiently. Of course that means the ability to focus manually thourgh the OVF is related to the focal length. The Samyang 16/2 will be OK wide open, the Samyang 24/1.4 needs to be stopped down to at least f/2.8, on the Pentax K50/1.2 it's f/4, etc... For a 85mm lens, I imagine even f/8 might be hard pressed. I know I always use LiveView on my Samyang 135/2. The longer the focal length, the easier it gets to focus via the OVF in my experience. If you use PDAF, for focus comfirmation, it should also be accurate for apertures of f2.8 or smaller (the weakness of PDAF is, that you can't do focus calibration for MF lenses individually though, so this might be no option for certain lenses)

07-30-2021, 03:30 AM	#32
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,210	Originally posted by othar the weakness of PDAF is, that you can't do focus calibration for MF lenses individually though, so this might be no option for certain lenses This should not be a problem generally. Most situations where PDAF confirmation is not working well for MF lenses, are due to the AF sensor being out of tolerance. A global adjustment in the AF-FA menu using the APPLY ALL setting should work well for all MF lenses....it does for me. If you have a fast MF lens that suffers from "focus shift" you may not get optimum results using this method, and as you note, you cannot make an individual adjustment for that one lens.

07-30-2021, 12:31 PM - 1 Like	#33
Wasp Pentaxian Join Date: Mar 2017 Location: Pretoria Photos: Gallery Posts: 4,661	When you get it right, the thin depth of field yields great results - Samyang 85mm f/1.4 on Samsung NX100 at f/2. Much easier to focus with a live view screen than with a mirror and a prism.

07-30-2021, 06:48 PM	#34
davidreilly3207 Loyal Site Supporter Join Date: Sep 2009 Location: South Jersey Photos: Gallery \| Albums Posts: 720	Originally posted by othar Why not, I get accurate focus afterwards? Not sure what your question is. If the diopter is adjusted using the info area text you will get an accurate focus of the subject matter.

07-30-2021, 09:59 PM	#35
wadge22 Veteran Member Join Date: Jun 2021 Location: NE Ohio Photos: Albums Posts: 897	Originally posted by othar Why not, I get accurate focus afterwards? I think you don't want to do it that way because that relies on the lens being focused correctly on the screen (which itself must be shimmed right) AND the diopter then correcting focus on that image. If the subject isn't focused on the focusing screen, no adjustment of the diopter will be right, and possibly the wrong one will make the image look best to you. The info area (or the black guide lines, which I tend to use) doesn't have that problem, it stays right where it is so you can set your diopter correctly on that every time. Originally posted by othar The longer the focal length, the easier it gets to focus via the OVF in my experience. Are you sure? I thought it was the opposite. It's quite possible that differences in the distance to the subject for whatever is commonly shot with those lenses makes it hard to say. Again messing around with a DOF calculator may be useful, although now you have me questioning myself even after consulting it. Have you tried a manual focus 300mm f2.8? By your guidelines, that should be a cakewalk even wide open... Also don't street shooters generally choose something in the short to normal range largely because of focusing advantages? Anyone able to clarify? P.S. I'm not trying to pick on you. Just trying to understand it myself.

07-31-2021, 01:10 AM	#36
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	Originally posted by wadge22 I think you don't want to do it that way because that relies on the lens being focused correctly on the screen (which itself must be shimmed right) AND the diopter then correcting focus on that image. If the subject isn't focused on the focusing screen, no adjustment of the diopter will be right, and possibly the wrong one will make the image look best to you.The info area (or the black guide lines, which I tend to use) doesn't have that problem, it stays right where it is so you can set your diopter correctly on that every time. My first step is focusing the lens via Live View, then I adjust the diopter so I see the same area sharp. How should the focus differ afterwards? Originally posted by wadge22 Are you sure? I thought it was the opposite.It's quite possible that differences in the distance to the subject for whatever is commonly shot with those lenses makes it hard to say.Again messing around with a DOF calculator may be useful, although now you have me questioning myself even after consulting it. The problem is, the wider the lens, the more surroundings are in the frame -> the smaller the borders between in-focus and out-of-focus areas appear in the viewfinder and it gets harder to pinpoint the exact area in focus. Originally posted by wadge22 Have you tried a manual focus 300mm f2.8? By your guidelines, that should be a cakewalk even wide open... I don't own a tele lens that fast, but focusing my Tokina 400mm f5.6 lens is a piece of cake opposed to my Samyang 35mm f1.4 lens. Another aspect to take in mind is: the longer the lens the greater your subject isolation -> you don't need to use apertures as fast as with wide or normal lenses to achieve a good separation from the background. Originally posted by wadge22 Also don't street shooters generally choose something in the short to normal range largely because of focusing advantages? In my opinion: no. The problem of too long lenses for street photography is that you don't get enough information of the surrounding area in the frame. You usually want to show what people are doing or where they are going, to give the viewer some context. With tele lenses you might get good headshots, which can look good depending on how expressive the face is, but if you are just interested in the faces you typically do portraits in a studio where you can also controll the light. Another problem of tele lenses for street photography is, that you have to back up a great deal to get an interesting framing and for small alleys or side streets there is often not the space to do so. With long lenses you also create a somewhat voyeuristic vibe, both for the people you photograph and for the people looking at the final image because of the compression and rendering tele lenses introduce to the image.

07-31-2021, 12:26 PM	#37
brightseal Site Supporter Join Date: Dec 2015 Photos: Albums Posts: 629	Originally posted by othar My first step is focusing the lens via Live View Do you then turn off live view and use the viewfinder or keep it in live view?

07-31-2021, 12:39 PM	#38
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	Originally posted by brightseal Do you then turn off live view and use the viewfinder or keep it in live view? Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise

07-31-2021, 02:39 PM - 1 Like	#40
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	Originally posted by brightseal What I meant was, after you make the adjustments do you still use LV. Are you making the adjustments once or for every pic. Once per day, after that I don't need LV anymore (with the exception of when the camera is on a tripod, then I use LV of course)

08-01-2021, 04:51 AM	#41
Wasp Pentaxian Join Date: Mar 2017 Location: Pretoria Photos: Gallery Posts: 4,661	Originally posted by othar Yes, I turn LV off and look through the OVF to adjust the diopter setting after that. I don't see how it would be possible to adjust the diopter setting to see the same area sharp as I did in LV otherwise Interesting approach, no problem with it. Except when you wear multifocal prescription glasses because the diopter that your eyes need depends on the distance that you are focusing at. The corrections for close up (0.5m), medium distance (about 3-5m) and infinity differs This means that for me, the diopter correction in the viewfinder is of little use. Besides, it also means that I have to take my glasses off to shoot and then put them back on to view the rear screen.

08-01-2021, 06:28 AM - 1 Like	#42
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by Wasp Interesting approach, no problem with it. Except when you wear multifocal prescription glasses because the diopter that your eyes need depends on the distance that you are focusing at. The corrections for close up (0.5m), medium distance (about 3-5m) and infinity differs This means that for me, the diopter correction in the viewfinder is of little use. Besides, it also means that I have to take my glasses off to shoot and then put them back on to view the rear screen. That’s odd. I wear that type of glasses and haven’t found that an issue at all for using the viewfinder. I have a massive astigmatism and a large diopter requirement so taking off my glasses isn’t an option. I simply look through them and adjust based on the info below the screen, I don’t recall any issues.

08-01-2021, 07:06 AM	#43
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,210	Originally posted by UncleVanya That’s odd. I wear that type of glasses and haven’t found that an issue at all for using the viewfinder. I have a massive astigmatism and a large diopter requirement so taking off my glasses isn’t an option. I simply look through them and adjust based on the info below the screen, I don’t recall any issues. I find that odd too. I use my distance glasses when taking pictures. Setting the dioptre for me is done without a lens. Just concentrate on the grid lines or info display and get them sharp. The point of dioptre adjustment is to dial in the right "prescription" so that you can see the focus screen clearly. The distance of your subject when taking a picture is irrelevant.....it is the lens that produces a sharp image on the screen, not your specs or dioptre adjustment.

08-02-2021, 09:14 PM	#44
Zafar Iqbal Veteran Member Join Date: Oct 2010 Photos: Gallery Posts: 1,229	Had this lens and found it to be really hard to use (portraits). I had changed to a better focusing screen and also used Live View a lot. The focusing ring being hard and very sensitive didn't help. Honestly, I don't miss it.