f/1.4 Question

JeremyLangford

JeremyLangford

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Ok. I have a Miinolta SRT-101 with a Rokkor 50mm f/1.4.

I have always loved this lens, but hadn't taken many pictures with it. Last week I went to Damascus, Virginia with my family and tried taking some pictures of all the ausome fall colors, and when I got my pictures back, I realized that my DOF was way to shallow in some of the close ups. I know the DOF should of course be shallow when using an f/1.4, I just didnt see that it was too shallow until I got the pictures back.

Here are some examples.

n3uic8.jpg



357oze1.jpg


Anyways, my question is, would it be fine for me to just use my DOF preview and take the aperture up or does this hurt the sharpness a lot? It seems like I always hear that you shouldn't take your aperture up, but instead just buy a higher aperture lens.

So basically, if I need an f/2.8 for my DOF to be right, should I take my 50mm f/1.4 to f/2.8, or should I buy a 50mm f/2.8 and use it wide open?
 
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You will get maximum sharpness from your lens at F5.6 to f11. Using the lens wide open is not the best if you want sharpness. Your 1.4 lens will function well at a smaller aperature but you will also have a very fast f1.4 if you need it for low light. Close down your lens and you will increase your depth of field.
 
In this case, with all the fall colors, I would have tried to shoot more stopped down (to include more detail), and used the lens more wide open for isolating detail against a colorful background, like the bottom shot.

:)
 
JeremyLangford said:
It seems like I always hear that you shouldn't take your aperture up, but instead just buy a higher aperture lens.
Click to expand...

You will be fine with your 1.4 lens upto f8 at least. Lens performance usually starts to degrade
above f11 or f16 due to defraction, below and including f8 it likely improves.

Best,

Roland.
 
alright sweet. I am very happy to have an f/1.4 then.

Here are some of the pictures that I ended up liking from the trip.

bj8u2h.jpg


oaq145.jpg


2iq5bc.jpg


2nrgh0i.jpg


ayou2g.jpg


160c3mg.jpg
 
JeremyLangford said:
Anyways, my question is, would it be fine for me to just use my DOF preview and take the aperture up or does this hurt the sharpness a lot? It seems like I always hear that you shouldn't take your aperture up, but instead just buy a higher aperture lens.
Click to expand...

I don't know of any lens that is at its sharpest wide open, but a good f/2 lens might indeed be sharper at f/4 than a good f/1.4 lens.

Oh, and many modern focusing screens can only gather light up to a certain aperture. You can test for yourself if there is any difference when using the DoF preview at f/2, for instance.

2c, /Jobo
 
Nice shots. The bokeh is very similar to that on my 50/1.7 Rokkor -- it looks really nice in some shots and a little weird in others. Wonder if that's a Rokkor design thing...
 
f1.4 is one of those things where you shouldn't do it just because you can. Also, the further away you are from your subject, the larger the DOF will be at f1.4. 10ft away and it's about 4ft or so. 3 ft away and it's only inches. You just have to get used to actually working with a lens to get the feel of it. One of the reasons I only use primes is that I understand the behavior of each lens and what I can do with it.

As a rule a lens that has a maximum aperture of f1.4 won't be as sharp at say f2.8 as a lens that starts at f2.0. But with quality lenses you hardly notice the difference. So there is no need to buy a slower lens.
 
It was recommended to me to hold the DOF preview down and slowly stop the lens down to see the effect of the different F stops on the DOF. That was for a Nikon SLR so I don't know about Minolta SLRs but I am guessing it would be OK too. As you stop the lens down the view gets darker making it harder to see the differences. The second set of photos look fine to me.

Bob
 
I agree with Nikon Bob - use the DOF preview button, it's there for a reason. By stopping down to the taking aperture you'll see what DOF you are going to get. Just because you have f/1.4 at your disposal doesn't mean taking all shots at that aperture. There should be a compelling reason to do so, either artistic or just plain lack of light.

Some of the shots you posted are just too shallow DOF, others exploit the same thing very nicely (only my personal opinion, feel free to disagree). The car headlight, for instance, is maybe a bit extreme and I think the shot of the steps is also too shallow. For me it would have been better to get more steps in focus while keeping the background blurred. On the other hand the second set of shots I would say there isn't actually a bad one there.

It's true to say that, generally, a fast lens like a f/1.4 is never as sharp as an f/2, there are more compromises in the design. In reality, however, the difference is quite small and usually only shows in demanding shots and high magnifications. The main penalties of a fast lens are greater weight, bulk and cost.
 
There is a review of the Minolta 1.4s here which may help you understand what you can expect from your specific lens at different apertures.
 
Nikon Bob said:
It was recommended to me to hold the DOF preview down and slowly stop the lens down to see the effect of the different F stops on the DOF. That was for a Nikon SLR so I don't know about Minolta SLRs but I am guessing it would be OK too. As you stop the lens down the view gets darker making it harder to see the differences. The second set of photos look fine to me.

Bob
Click to expand...

This is one reason I love my SRT-101.

The DOF preview actually stays on after you press the button and goes off with another press. This can come in handy with a f/1.4 sometimes.
 
wolves3012 said:
I agree with Nikon Bob - use the DOF preview button, it's there for a reason.

Some of the shots you posted are just too shallow DOF, others exploit the same thing very nicely (only my personal opinion, feel free to disagree). The car headlight, for instance, is maybe a bit extreme and I think the shot of the steps is also too shallow. For me it would have been better to get more steps in focus while keeping the background blurred. On the other hand the second set of shots I would say there isn't actually a bad one there.
Click to expand...

Thank you. I agree with you and I was surprised to see how shallow my pictures actually turned out when I saw them on the computer.
 
cmedin said:
Nice shots. The bokeh is very similar to that on my 50/1.7 Rokkor -- it looks really nice in some shots and a little weird in others. Wonder if that's a Rokkor design thing...
Click to expand...

Ha. I started out with that lens. I love both of them.
 
Jeremy,

Welcome to the wonderful world of the fantastically versatile 50/1.4 lens.

A few samples that I think show the versatility.

EDIT: Fix links

The two links are of subjects just a few feet apart and photos taken a few minutes apart. Same film/body/lens. The first at about f=5.6 and the second at or very near f=1.4. Both close to minimum focus distance. I know the 1.4 photo was very close to minimum distance.

Sample @ 5.6 or 8.0

Sample @ 1.4
 
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