Nikon 50mm F/1.4 MF focusing issues

[steve_kraft]

I have done some searching on this issue, and couldn't find any pertinent

information. If there are any similar threads, please point me in the right

direction.

 

Anyhow, I have a D70 and am having fun with my father's 4 Pre-AI, MF, prime

lenses. One of them is a 50mm 1.4. I have been able to take some amazing shots

with it, enjoy the bokeh it produces and have a lot of fun with it. However, I

am having problems with both the accuracy and precision of focusing the lens.

To get the right focusing distance, I have to take a few shots and examine them

on the LCD screen to see which one came out right. It seems that the focusing I

see in the viewfinder is not matching up with what is taken by the camera.

 

What could be the problem?

 

Thank you,

 

-Steve

[tri-x1]

I don't have a Nikon digital SLR but I seem to remembering seeing somewhere that the digitals do have focusing issues with MF (at least some) lenses.

[todd peach seattle, washi]

The D70 viewfinder is simply not up to the task. You can't discern the 'in focus' point adequately with it. It has been idealized for autofocus and f/2.8 (or slower) lenses. It does not have enough 'tooth' to focus a fast lens precisely (not enough tooth means the image always sort of looks like it's in focus). If they made the screen toothy, it would look unacceptably dim at f/4.5 or so.

 

I have had a fair amount of experience with various Nikon cameras and lenses, and I just would not use a D70 for critical manual focusing (I had my 'comeuppance' with it using an 80-200mm f/2.8 wide open at 200mm)

 

The D200 is better in this regard. However, I have come to the conclusion that if you really want to shoot fast lenses like the 85/1.4 or 135/2.0 wide open on a digital, you need a D2H (or similar) body to ascertain exactly where your focus point is (by examining the viewfinder image).

[rcoder]

Basically, the short answer is that MF of any sort on the D70 is hard to pull off -- the size of the sensor and viewfinder don't leave you with much image to work with when you're focusing. When I want to shoot manual, I pull out my old OM-1 kit.

 

You might have better results using the focus indicator in the lower-left corner of the viewfinder; it indicates that the camera belives *something* to be in focus, though it may not be your particular subject.

[neil_parker]

It's the viewfinder/focusing screen. The D70 and other digital nikons (& other brands) have

screens that are bright and optimized for AF use, they lack the 'tooth' to accurately

manually focus a lens, especially a fast lens with no margin for error. I have the same

problem with my D200, which has a better viewfinder than the D70. I believe that the

smaller size of the view compared to 35mm is part of the problem also.

 

I can achieve focus by using the green light in the viewfinder, but not consistently or fast

enough for a situation where I am trying to capture images from people who are moving.

It's a bit depressing to use my F3 and then return to the D200, it's like going from

cinemascope to TV. Some people recommend the Katzeye screen, a replacement focusing

screen optimized for manual focus.

[steve_kraft]

Thank you all for the responses, so far.

 

It seems I'm out of luck. So if I like this lens and want to couple its speed and photographic characteristics with my D70, should I go for a modern, AF-D version of the same lens, or perhaps the 1.8?

 

-Steve

[ky2]

Take a look at katzeye optics (google it), they have a replacement screen that can assist in focusing. I did the upgrade for my D200, and I mainly use manual focus glass with that camera.

[aardvarko]

The li'l "in-focus" dot usually does a reasonable job. Trust it.

[ky2]

<i>"The li'l "in-focus" dot usually does a reasonable job"</i><br><br>

No it doesn't. It's fine for for lenses with deep DOF, but sucks at f/1.4 on any lens.

[Ed_Ingold]

Does a pre-AI lens fit the D70 without causing damage? You will find a compatibility chart in the D70 specs at http://www.nikonusa.com.

 

For focusing, rough-in with the ground glass and fine tune (if necessary) with the green dot and arrows. Learn to manually focus correctly - focus past the sharpest point, back up to equal unsharpness then split the difference. I hardly ever have to use the dot, at least with a D1x or better.

[ShunCheung]

Your eyesight may be better than mine, but I had a lot of trouble focusing Yaron's 50mm/f1.4 Zeiss ZF on my D2X. It can only be a lot worse on the D70. At least IMO, a K type split-image focusing screen, such as the KatzEye, is a must for manual focusing.

[studor13]

Steve, first you need to see if the AF is dead on. That is, shoot at some standard test chart at 45 degrees and make some analysis. If it is then you are in luck because you can then test a shot that is in focus to your eye through the VF against an image that is in focus as seen by the focus assist indicator.

 

Remember that you need something that has clear contrast, such as a line,(or hair and forehead) for the focus assist indicator to lock. And use a tripod when testing.

 

If your AF is accurate but only a back focus problem when using MF, then you can adjust something inside your D70 and it's fairly easy. You can even adjust the AF, but I didn't have this problem and also it's a bit trickier to adjust.

 

I asked this question a couple of weeks ago and managed to work it out myself and I documented the links I used to solve the problem so let me know if you need that thread, or can't find it.

 

I don't have an f1.4 lens but occasionally use an f2.8 lens and I trust the little focus indicator more than my eye sight. Now I really enjoy shooting wide open because with a great lens even though the VF is crap, the results are amazing.

[Peter_in_PA]

One other issue you have, Steve, is that with f1.4 wide open, very little is in fact in focus. The

depth of field is so limited because of the wide aperture. I know it's a simple thing, but so far

no one has mentioned it. I even find this to be the case with my 50/1.8. I shoot, the image is

in focus, it even looks okay on the monitor, but on the computer screen it's soft. Stopped

down to 5.6 or 8 and I'm okay.

[alan_olander1664878205]

As Edward said, you could damage your D70 by mounting a "pre-AI" lens on it.

[Ed_Ingold]

Actually, I didn't say because I don't know. I do know that cameras with an aperture coupling ring (D1/2/200 for example) will be damaged. AI lenses have a cutout in the aperture adjusting ring to engage a tab in the lens mount, but not pre-AI lenses. The coupling ring tab on my F3 folds out of the way.

[steve_kraft]

Thank you all again for the thorough and prompt responses.

 

I have tried the lens and used the green dot with much better results. I was unaware that the camera could recognize if the image was in focus using such an old lens, and had overlooked that feature previously - thank you all.

 

Yes, at 1.4, very little is in focus, and additionally the lens as has been pointed out, gets soft, but occasionally that is a desired effect. I was aiming for this sometimes but would find that my subject's eyebrow or eyelid would be in focus instead of their eye and I had botched an otherwise excellent shot. I think I should perform better now, and might try a new focusing screen. If I don't get good results at that point I might just spring for an AF 1.8 lens.

 

Concerning the fact that the Pre-AI lenses might damage the camera, while this will be debated for a while on these forums, I had asked this question here before and a few other seemingly trusty Nikon users were confident that the lenses were safe as long as I mounted them at the correct aperture setting. I have been careful and seem to have done no damage when inspecting the camera, and even if I did overlook some on the interior, the functionality has not been compromised in the past 8 months of doing this and using the camera quite a bit.

 

Thanks again,

 

-Steve

[alan_olander1664878205]

The damage that can occur is to the minimum aperture signal lever which is located just above the depth of field preview button. It doesn't matter which aperture you have the lens set to when you mount it to the camera.

[sjmurray]

I have a bunch of pre-AI lenses. A couple I had converted by a shop to AI, and on a couple I used a Dremel tool to grind off a bit of the aperture ring so it would clear the little tab that fits in the slot of an AI lens. You should check out this little black tab to make sure you haven't damaged it. Otherwise, I have been shooting with a 50mm 1.4 as well. At least it is very bright in the screen, but it does take some scrutiny to get sharp focus, especially at 1.4 or 2.0. I have to make sure my diopter setting is "right on" so I am seeing a sharp image.

[mawz]

All Nikon AF bodies which lack AI coupling have a small switch around the 7 O'clock position when looking at the front of the camera. This switch engages a tab on AI and later lenses to indicate they are at minimum aperture. The switch is also notably more fragile than AI coupling tabs. Pre-AI lenses may damage this tab if not converted correctly. Some Pre-Ai lenses and accessories are safe (I've confirmed the M2 ring is safe, barely).

 

Also try a DK-21M eyepiece magnifier, it improves the D50 and D70 viewfinders immensely when used with MF lenses.

[hique]

It could be that you are not seeing right. Maybe it's time to make an eye exam.

 

Maybe the Diopter settings is not correct.

 

And finally, maybe it's the fact that the D70 viewfinder is the crappiest of all DSLR I've ever seen. I would never try to manual focus a lens with it. It's really not up to the task, as someone pointed.

 

I guess it's a bit of all of these problems.

 

Good luck

[wei_who]

I have D70 and 50mm 1.4 MF lens. I use the old way: a tape measure (a small laser/digital version from home improvement center, cost less $10)! It works very well every time even near dark.