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Having some issues with manual focus
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PostPosted: Thu Feb 18, 2021 7:38 am    Post subject: Having some issues with manual focus Reply with quote
Hi Everyone:

I have been using a Sony A7ii and the CZJ 58mm Biotar wide open at f2, and unlike my other manual lenses I seem to be having trouble focusing with this lens. I am using double magnification. The problem I think is either glare or simply a dark view through the viewfinder. In fact, if I put my hand over and around the viewfinder, I can see much better, but it is more difficult to use the focus ring with that hand. So I have resorted to leaning back and forth with my body until I find the right focus (I keep the focus ring at the closest possible focus). I can understand why a shorter lens would represent more difficulty focusing, but I have not experienced such issues with several manual lenses before although they were generally longer lenses.

Does anyone have any suggestions that may be helpful?

Thanks,

-Charles


PostPosted: Thu Feb 18, 2021 9:05 am    Post subject: Reply with quote
What does the glass look like when you shine through it with a flashlight?


PostPosted: Thu Feb 18, 2021 1:11 pm    Post subject: Reply with quote
If the glass is ok. check the apeture on the canera and minimise it, I have one lense that I always find this is wrong for. The result is the view is dark and it essentially adds the apeture on the camra to the apeture, sorry if this is off track.


PostPosted: Thu Feb 18, 2021 1:34 pm    Post subject: Re: Having some issues with manual focus Reply with quote
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Last edited by Blazer0ne on Tue Feb 22, 2022 6:04 pm; edited 1 time in total


PostPosted: Thu Feb 18, 2021 1:58 pm    Post subject: Reply with quote
Moving backwards & forwards is the best way for perfecting focus at macro distances, it doesn't work at all for landscapes Smile

The further comment on keeping the focus ring at it's minimum confirms to me you are shooting close-up/macro which will help explain the dark viewfinder & also how critical focusing can be - at higher magnifications DOF can be less than 1mm. Mounting the camera on a tripod & focus rail can help considerably for macro of static subjects. Otherwise you probably want flash to prevent camera movement blurring your images completely.
Menu settings on the A7ii will enable you to boost the viewfinder brightness making it much easier than a DSLR in low light.

Fitting a lens hood will have the same effect as shading the lens with your hand - while leaving both hands available to control the camera. A rubber screw in type that mounts on the filter threads is generally effective & cheap. They can be awkward if you don't have much working distance.

I have focus peaking enabled on my A7ii but find it doesn't help with some lower contrast lenses. I usually also magnify the image in the viewfinder to various extents but usually only after initial framing & rough focusing.


PostPosted: Thu Feb 18, 2021 2:52 pm    Post subject: Reply with quote
I have the same problem with my A7ii sometimes. A couple of settings that can help is the Viewfinder Bright - set it to manual and increase the brightness to maximum, and the Live View Display - maybe will have no effect but worth turning off to try. Also set the Display Quality to High as that helps with manual focusing.

I too find I need to shade the viewfinder sometimes but then you need three hands. I've not found a solution to that. It needs a bigger eye-cup.


PostPosted: Thu Feb 18, 2021 5:14 pm    Post subject: Reply with quote
caspert79 wrote:
What does the glass look like when you shine through it with a flashlight?


I always check for fungus or haze when I first receive a lens. This lens is fairly clean!


PostPosted: Thu Feb 18, 2021 5:16 pm    Post subject: Reply with quote
Slalom wrote:
If the glass is ok. check the apeture on the canera and minimise it, I have one lense that I always find this is wrong for. The result is the view is dark and it essentially adds the apeture on the camra to the apeture, sorry if this is off track.


Sorry, what do you mean by minimize it on the camera? I am shooting wide open with a manual lens. I though the aperture can only be set with the lens?.


PostPosted: Thu Feb 18, 2021 5:21 pm    Post subject: Reply with quote
DConvert wrote:
Moving backwards & forwards is the best way for perfecting focus at macro distances, it doesn't work at all for landscapes Smile

The further comment on keeping the focus ring at it's minimum confirms to me you are shooting close-up/macro which will help explain the dark viewfinder & also how critical focusing can be - at higher magnifications DOF can be less than 1mm. Mounting the camera on a tripod & focus rail can help considerably for macro of static subjects. Otherwise you probably want flash to prevent camera movement blurring your images completely.
Menu settings on the A7ii will enable you to boost the viewfinder brightness making it much easier than a DSLR in low light.

Fitting a lens hood will have the same effect as shading the lens with your hand - while leaving both hands available to control the camera. A rubber screw in type that mounts on the filter threads is generally effective & cheap. They can be awkward if you don't have much working distance.

I have focus peaking enabled on my A7ii but find it doesn't help with some lower contrast lenses. I usually also magnify the image in the viewfinder to various extents but usually only after initial framing & rough focusing.



Actually, I am shooting only portraits, but this lens does not allow me to get too close, something like 5 feet is the closest I can get. Great suggestion about the viewfinder brightness setting. i shall look for it right now. A lens hood is also a good idea! But the filter thread is 40.5mm which is not ideal.


PostPosted: Thu Feb 18, 2021 5:25 pm    Post subject: Reply with quote
monopix wrote:
I have the same problem with my A7ii sometimes. A couple of settings that can help is the Viewfinder Bright - set it to manual and increase the brightness to maximum, and the Live View Display - maybe will have no effect but worth turning off to try. Also set the Display Quality to High as that helps with manual focusing.

I too find I need to shade the viewfinder sometimes but then you need three hands. I've not found a solution to that. It needs a bigger eye-cup.


Yes, the viewfinder brightness is a superb idea! I don't have the live view display turned on. I only use the display to view after I take the image. I am going to check whether larger eye cups are available for my Sony model. What I find if I need to shade with my left hand is that I can do what I do for macros... lean forward and back to adjust for focus. Thanks again for your great ideas!


PostPosted: Thu Feb 18, 2021 6:24 pm    Post subject: Reply with quote
charley5 wrote:

Actually, I am shooting only portraits, but this lens does not allow me to get too close, something like 5 feet is the closest I can get. Great suggestion about the viewfinder brightness setting. i shall look for it right now. A lens hood is also a good idea! But the filter thread is 40.5mm which is not ideal.


I think I've got a lens or two with 40.5mm threads - an awkward size but it should be simple enough to get a stepping ring to 43mm, 46mm, 49mm or 52mm which are all more common sizes and not too much bigger.
See: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=m40.5+step+up&_sacat=625&LH_TitleDesc=0

What mount is your Biotar? If it's M42 then you could adapt it via a helicoid which will give extra extension at a twist of the ring gaining you closer focusing. Probably not such a good idea for portraits as getting too close will cause perspective issues, 5' is about the closest that's practical without this being an issue.


PostPosted: Thu Feb 18, 2021 6:30 pm    Post subject: Reply with quote
DConvert wrote:
charley5 wrote:

Actually, I am shooting only portraits, but this lens does not allow me to get too close, something like 5 feet is the closest I can get. Great suggestion about the viewfinder brightness setting. i shall look for it right now. A lens hood is also a good idea! But the filter thread is 40.5mm which is not ideal.


I think I've got a lens or two with 40.5mm threads - an awkward size but it should be simple enough to get a stepping ring to 43mm, 46mm, 49mm or 52mm which are all more common sizes and not too much bigger.
See: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=m40.5+step+up&_sacat=625&LH_TitleDesc=0

What mount is your Biotar? If it's M42 then you could adapt it via a helicoid which will give extra extension at a twist of the ring gaining you closer focusing. Probably not such a good idea for portraits as getting too close will cause perspective issues, 5' is about the closest that's practical without this being an issue.


I actually have stepping rings at home. I'll look for a 40.5 link but I live in India so not always easy to get stuff that is off the mainstream....


PostPosted: Thu Feb 18, 2021 6:56 pm    Post subject: Reply with quote
[quote="charley5"]
monopix wrote:
Yes, the viewfinder brightness is a superb idea! I don't have the live view display turned on. I only use the display to view after I take the image.


There should be a setting called Preview Exposure or something (I don't know what it's called on Sony). If you turn off Preview Exposure the LCD and EVF will show you a bright image even in low light, even with the aperture closed down.

It's basically cranking the ISO up super high, but only for the LCD and EVF, not for the actual image.


PostPosted: Fri Feb 19, 2021 2:47 pm    Post subject: Reply with quote
[quote="KEO"]
charley5 wrote:
monopix wrote:
Yes, the viewfinder brightness is a superb idea! I don't have the live view display turned on. I only use the display to view after I take the image.


There should be a setting called Preview Exposure or something (I don't know what it's called on Sony). If you turn off Preview Exposure the LCD and EVF will show you a bright image even in low light, even with the aperture closed down.

It's basically cranking the ISO up super high, but only for the LCD and EVF, not for the actual image.


Interesting. I shall definitely check it out. Thanks!
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