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05-13-2016, 08:55 AM   #16
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@Cuthbert

On K-1 (and pretty much any Pentax digital camera I think) an A lens allows the user to set the aperture from the camera body (when the lens is in the A aperture position) using one of the eDials. In Av Mode the camera will calculate an exposure value with open-aperture metering using that aperture setting (K-1 metering so far feels quite accurate), and will adjust shutter speed and/or ISO to produce a well-exposed image.

You will still need to input the focal length of the lens every time you mount it or turn the camera on.

Auto focus lenses identify themselves to the camera, and Firmware has a lens profile the camera uses to calculate an accurate exposure as you adjust aperture or shutter speed (or ISO).

In Manual Mode you can control all aspects of the settings yourself, either on the lens or the camera.


Last edited by monochrome; 05-13-2016 at 11:11 AM.
05-13-2016, 09:11 AM   #17
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QuoteOriginally posted by Cuthbert Quote
For the K50, I am not interested in a non full frame camera as all my lenses wouldn't work as on a film camera, but on the K-1 at least can the A lenses work properly? Is there an aperture priority mode where I can define the f stop and DOF I want?
The K-1 is a full-featured camera. With the exception of full compatibility with standard K-mount, I doubt that you would find much to quibble with moving from your current stable of film cameras. As noted on this thread, manual focus can be a challenge, but that is pretty much the case across the board any more regardless of brand or price point for dSLRs with stock focus screen.*


Steve

* The manual focus issue was a problem with AF film cameras as well. PDAF requires a half-silvered main mirror. As a result, focus screens were designed to optimize brightness at the expense of focus sensitivity and magnification is lower (DOF is exaggerated). Most higher-end dSLRs (K-1 excepted) support changeable screens, but I believe that Canon is alone in offering screens useful with fast lenses.

Last edited by stevebrot; 05-13-2016 at 09:33 AM.
05-13-2016, 09:25 AM   #18
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QuoteOriginally posted by monochrome Quote
I sort of think it is either aperture coupler lever and a bigger camera or stop-down Green Button metering and a small camera.
That is hard to say. The cut-away photos I have seen of the K-1 and even the APS-C cameras appear to show that space as unoccupied. On film cameras, the "follower" mechanism is very compact and fits within the arc of the mount with a depth of about 5mm and thickness of about 3mm max. I suspect it was dropped way back when as a cost-saving measure in manufacturing, being that it is one more mechanism that requires precision manufacture and assembly.


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05-13-2016, 10:07 AM   #19
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QuoteOriginally posted by stevebrot Quote
Is it either/or


Steve
Space-wise, it very well could be! In any case it would cost extra development time.


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05-13-2016, 10:35 AM   #20
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QuoteOriginally posted by Cuthbert Quote
Second thing, is there a split screen available that will help focusing with fast (f1.2) lenses?
I'm an all manual man and have used KatzEye split screen micro collar screens for the last eight years and worried about the this... as interchangeable screens are currently not an option.

Pleased to report so far the K1 screen is big and bright and ground screen with the green hexagon thingy has proved to be pretty accurate even with "Special Lady” (SMC Pentax-A 50mm F1.2).

I have tried the focus peaking function also, which is wonderful for my product shooting.
05-13-2016, 01:23 PM   #21
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QuoteOriginally posted by Cuthbert Quote
.

For the K50, I am not interested in a non full frame camera as all my lenses wouldn't work as on a film camera, but on the K-1 at least can the A lenses work properly? Is there an aperture priority mode where I can define the f stop and DOF I want?
Yeah, with all due respect I think you're out of touch, here, Cuthbert. ☺

I do this in aperture priority mode with A lenses, and in manual mode with K, M and M42 lenses as well - maybe some of the same ones you have!





05-13-2016, 02:25 PM   #22
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QuoteOriginally posted by clackers Quote
Yeah, with all due respect I think you're out of touch, here, Cuthbert. ☺
Why? It has already been said that with K and M lense the K-1 can't meter full open, I still have to understand if at least it would work with A lenses (no green buttom!).
05-13-2016, 02:36 PM   #23
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QuoteOriginally posted by Cuthbert Quote
Why? It has already been said that with K and M lense the K-1 can't meter full open, I still have to understand if at least it would work with A lenses (no green buttom!).
On an A lens, you set it at the "A" position, and you control aperture from the body.

05-13-2016, 03:41 PM   #24
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QuoteOriginally posted by Cuthbert Quote
I still have to understand if at least it would work with A lenses (no green buttom!).
Of course it does - this was explained to you in Posts 2 and 3.

Look, people have been shooting for years with these things! ☺

Have a look at the A Lens Club in this forum if you like. You can even find elsewhere from last week shots with the A50 f1.2 taken on the K-1.
05-13-2016, 04:23 PM   #25
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FWIW, I'm shooting K-1 and K400/5.6 at the moment. That lens is a preset, so I'm focusing at f/11 until the light changes. Just for grins I WiFi'd a 100 yard shot of a group of people to my phone. Green Button exposure looks spot on and totally manual focus looks very sharp (I'll post samples when I get home). Viewfinder is luscious.

Last edited by monochrome; 05-13-2016 at 04:33 PM.
05-13-2016, 04:43 PM   #26
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QuoteOriginally posted by Cuthbert Quote
Why? It has already been said that with K and M lense the K-1 can't meter full open, I still have to understand if at least it would work with A lenses (no green buttom!).
That depends what you mean by 'meter full open'. I think there may be a couple of cross wires in this thread. Read this post a couple of times, and hopefully all will become clear!

In all cases (M/K/A/F/FA/DA/DFA) lenses will be wide open when you are metering.

With all lenses with the 'A' setting on the aperture ring (ie everything apart from 'M' and 'K'), you will need to ensure that the aperture ring is set to 'A'. To choose the aperture you will typically use the rear dial on the camera body itself (IMPORTANT: the camera knows the f-stop), unless you are using an AUTO mode of some sort (the camera will still know the f-stop!). This does not require a green button. It's easy, and a nice user experience. The only difference between 'A' lenses and all the later lenses, is the lack of autofocus.

With 'M' and 'K', things differ slightly. Metering still happens with the lens fully open, BUT! The camera has no way of telling what F-Stop you've got selected (the crippled K mount removed the mechanical linkage). Because it does not know the f-stop, it can't guess the correct shutter speed. So if you are in AV/AUTO/TV etc, the selected f-stop on the lens is ignored completely, and the shot will always be taken wide open, and the exposure will always be correct.

IF you want to select an f-stop, then you will need to use the 'M' mode on the camera and the green button. Choose the aperture you want on the lens, compose and focus your shot, hit the green button to meter (this is called 'stop down metering'), and then click the shutter to take the shot.

So with 'M' and 'K' glass, you can use the K-1 as a point and shoot by simply selecting say AV mode, and click away to your hearts content. Metering will be correct, but the lens will always use the largest aperture. If you want to use a different aperture, you'll need to use the green button and manual mode.

With 'A' glass, just set the camera to AV. The rear dial will now control aperture. Everything will meter correctly. If you have FA or DFA lenses, the behaviour is the same, except you also have autofocus available.

I hope that makes sense?
05-13-2016, 05:16 PM   #27
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QuoteOriginally posted by robthebloke Quote

With 'A' glass, just set the camera to AV. The rear dial will now control aperture. Everything will meter correctly. If you have FA or DFA lenses, the behaviour is the same, except you also have autofocus available.

I hope that makes sense?
Ok that's clear, but will it work just in Av mode? What about Tv? I assume it should work with the program mode as well.
05-13-2016, 05:27 PM   #28
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QuoteOriginally posted by Cuthbert Quote
Ok that's clear, but will it work just in Av mode? What about Tv? I assume it should work with the program mode as well.
'A' lenses work in all modes (because they are the same as an FA, just lacking autofocus)

'M' and 'K' work in all modes, but with the caveat that an f1.7 -> f22 lens is treated as an f1.7 -> f1.7 lens. (Using manual mode and the green button is the only way around that)

---------- Post added 05-14-16 at 01:32 AM ----------

Well, so long as the 'A' lens is set to 'A' on the aperture ring. An 'A', 'F', 'FA' or 'DFA', when set to an aperture value that isn't 'A', has the same limitations as an 'M' or 'K'....
05-13-2016, 06:20 PM   #29
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QuoteOriginally posted by Cuthbert Quote
Ok that's clear, but will it work just in Av mode? What about Tv? I assume it should work with the program mode as well.
You'd be making a big jump from film to K-1 ... jumping ahead more than a decade. I understand you reluctance to purchase a "lesser" camera first, but frankly the best way for you to understand these answers is for you to handle a relatively current K-mount camera, such as a K-50.
05-14-2016, 01:15 AM   #30
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QuoteOriginally posted by reh321 Quote
You'd be making a big jump from film to K-1 ... jumping ahead more than a decade. I understand you reluctance to purchase a "lesser" camera first, but frankly the best way for you to understand these answers is for you to handle a relatively current K-mount camera, such as a K-50.
I beg to differ! I started off on 35mm pentaxes of old (and still do my own developing), and whilst I made the jump a few years ago, I never quite gelled with the APSC bodies (the k-3 came pretty close though!). If you've got a set of lenses that you're used to using on 35mm (say 28, 50, and 135), you end up with lenses that are of a slightly odd focal length, and just aren't able to give you the same results. adding a bunch of DA limiteds (say 21, 35, and 70) can get you somewhere close to that original 35mm set, but by that point you've now bought and APSC camera + lenses, which probably costs about as much as just buying an FF.

If you're used to the dynamic range of 35mm film, then the K-1 is quite a nice upgrade, and the k-3 is a pretty decent compromise. My 2 cents, others are sure to disagree!
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