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03-17-2009, 05:45 AM   #721
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Using Tv mode with M lenses

Today, I kind of realized that really you could use Tv mode with M lenses.

I tried it, and have got the perfect exposure on every shot.

Tell me if I am missing something, but it seems like it should work ... no?

Please let me know, because M lenses would be so much easier..

-Isaac

EDIT: I've been playing around with it, I've been getting perfect exposure, but the depth of field isn't changing with the aperture ..

Is there a way for the camera to pick the shutter speed automatically, and have it change when the aperture ring changes?


Last edited by IsaacSteiner; 03-17-2009 at 06:01 AM.
03-17-2009, 08:07 AM   #722
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QuoteOriginally posted by IsaacSteiner Quote
I have a question.

When I use either of my Pentax-M lenses (50mm F2 / 28mm F2.8) I find the photos to be over exposed. But since I shoot RAW I can fix it quite easily, but it'd be nice to have it almost perfect before hand.

So before I shoot, I set the aperture I want, then I click the green button, then focus, and shoot.

Any suggestions?

Thanks,

-Isaac
Isaac, I have found with my two M lenses that there are a series of stops that do give correct exposure readings. I tested and found also, that the mechanical exposure linkages provide consistent exposure. Thus, I conclude that metering is the problem. In the digital SLR there is no tracer for the aperture setting, and this seems to give the meter indigestion at some of the apertures.

I use the stop down preview method to set my exposure rather than the green button method. With both my lenses f/8 gives me a correct exposure reading (as long as I pay attention to what I am metering, of course) and I then interpolate from there.

Both my lenses are a bit slow so I cannot speak to what apertures will give correct exposure in your case. I suggest you take your lens and either play with the metering or use sunny 16 on an average scene to find which of your lens' apertures are accurate.

EDIT: Re message immediately above about using Tv. The camera is allowing you to set the shutter speed, but will not change the aperture in this instance. In both Av and Tv, the camera will only shoot with the lens wide open, no matter what stop you set on the aperture ring.

Last edited by Canada_Rockies; 03-17-2009 at 08:10 AM. Reason: Added answer to second missive from Isaac
03-17-2009, 08:49 AM   #723
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Pentax M 400mm with @x Rear Converter

Continuing my experiments with the M 400 today. I tried the Pentax K T6-2X on the M 400/5.6 this morning. I seldom use the 2X as it degrades the image too much for my taste but thought I should give it a try. Mounted on this lens with the digital dividend I guess I was working with about an 1100 mm f11 or so??? Depth of field is almost zero and clearly a tripod is a must for this puppy. ISO 100, shutter speed 1/40th sec. with aperture set about f8 to f 16. I think I need to raise both ISO and shutter speed for better results. In any case this was the best I could manage today.





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03-17-2009, 09:16 AM   #724
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QuoteOriginally posted by IsaacSteiner Quote
Today, I kind of realized that really you could use Tv mode with M lenses.

I tried it, and have got the perfect exposure on every shot.

Tell me if I am missing something, but it seems like it should work ... no?

Please let me know, because M lenses would be so much easier..

-Isaac

EDIT: I've been playing around with it, I've been getting perfect exposure, but the depth of field isn't changing with the aperture ..

Is there a way for the camera to pick the shutter speed automatically, and have it change when the aperture ring changes?
In Tv mode, the aperture remains wide open and changes to the aperture does not do anything. The only way to get the aperture to work is in Manual mode.

03-17-2009, 10:12 AM   #725
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QuoteOriginally posted by 8540tomg Quote
Continuing my experiments with the M 400 today. I tried the Pentax K T6-2X on the M 400/5.6 this morning. I seldom use the 2X as it degrades the image too much for my taste but thought I should give it a try. Mounted on this lens with the digital dividend I guess I was working with about an 1100 mm f11 or so??? Depth of field is almost zero and clearly a tripod is a must for this puppy. ISO 100, shutter speed 1/40th sec. with aperture set about f8 to f 16. I think I need to raise both ISO and shutter speed for better results. In any case this was the best I could manage today.
Tom G
Nice work with the 400. Considering the age of the lens, and the even older optical formula, it works pretty well, does it not? I'm actually pleasantly surprised at the first snap you posted.
03-17-2009, 10:52 AM   #726
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QuoteOriginally posted by Canada_Rockies Quote
Nice work with the 400. Considering the age of the lens, and the even older optical formula, it works pretty well, does it not? I'm actually pleasantly surprised at the first snap you posted.
Thanks Albert,

The first shot is OK but #2 - well - this is a work in progress. I don't use the 2x often and I'm certain that is a major factor in my lack of success with it. It sure gives you a lot of extra working room but it takes so long to get sharp focus that birds are often gone before you can trip the shutter. The angle of view is so narrow that a slight adjustment of the camera can knock the subject right out of the viewfinder. I'll keep plugging away from time to time just to see what this combo can do when I finally get things right.

Tom G

Last edited by 8540tomg; 03-17-2009 at 12:05 PM. Reason: typo
03-17-2009, 11:04 AM   #727
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QuoteOriginally posted by 8540tomg Quote
Thanks. First shot is OK but #2 - well - this is a work in progress. I don't use the 2x often and I'm certain that is a major factor in my lack of success with it. It sure gives you a lot of extra working room but it takes so long to get sharp focus that birds are often gone before you can trip the shutter. The angle of view is so narrow that a slight adjustment of the camera can knock the subject right out of the viewfinder. I'll keep plugging away from time to time just to see what this combo can do when I finally get things right.

Tom G
I use the 1.4X-S with the 400 successfully, but when I do, I have to use my Manfrotto (see my avatar). Even then, vibration can sneak in and ruin things. I usually set the ISO to 400 and the aperture to f/8 (f/11 equivalent). This allows me a shutter speed that works reasonable well. I recently bought a 1.7X af, and I will try that out with the 400 later in the year. Right now, there is so much snow around that the dreaded red fringes would ruin anything I shoot. Using a teleconverter just makes the fringes even wider. I use the shotgun sight to line up. After some practice, I can use it quite consistently to track and drop my eye to the viewfinder. Of course, I grew up with shotguns, so using that sighting method is now quite natural to me.

03-17-2009, 11:49 AM   #728
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M 150 f:3.5

The only M lens I've got is the M150 f:3.5, which I got on an LBA impulse. While the lens is not all that impressive wide open, it does produce nice images stopped down. Here a few examples:







Roger
03-17-2009, 01:06 PM   #729
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QuoteOriginally posted by IsaacSteiner Quote
Today, I kind of realized that really you could use Tv mode with M lenses.

I tried it, and have got the perfect exposure on every shot.

Tell me if I am missing something, but it seems like it should work ... no?

Please let me know, because M lenses would be so much easier..

-Isaac

EDIT: I've been playing around with it, I've been getting perfect exposure, but the depth of field isn't changing with the aperture ..

Is there a way for the camera to pick the shutter speed automatically, and have it change when the aperture ring changes?
If you are using an M lens and you set the exposure to Tv, the camera will default to Av mode. The same is true for P mode.

You will get a correct exposure in Av mode because the camera is setting a shutter speed for wide-open aperture. It does not matter what you set the aperture to on the lens, the picture will be taken at widest aperture. This is why your DOF is not changing.

The only way to have the camera select a shutter speed relative to your selected aperture is to use M .. manual exposure and press the green button.

The K10 is know to progressively overexpose with M and "K" lenses using this method as you stop down. Some lenses are better than others in this respect. The solution is to fit a DS screen or a LL-80 screen to your K10.

However if you like to focus manually you might prefer to fit a split prism focus screen, in which case you will have to allow for this progressive overexposure, by using the histogram to check your photos.
03-17-2009, 01:17 PM   #730
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QuoteOriginally posted by pschlute Quote
The only way to have the camera select a shutter speed relative to your selected aperture is to use M .. manual exposure and press the green button.
This is true, but I still prefer to use the dof preview and set the exposure using the scale. This allows me to set a preferred aperture, and still get correct exposure. Using the green button on any f/stop that does not meter correctly will give you an incorrect exposure. The only way I have found to use lenses that do not have the A setting is to use a known accurately metering f/stop and interpolate the exposure from there.
03-17-2009, 02:04 PM   #731
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QuoteOriginally posted by Canada_Rockies Quote
This is true, but I still prefer to use the dof preview and set the exposure using the scale. This allows me to set a preferred aperture, and still get correct exposure. Using the green button on any f/stop that does not meter correctly will give you an incorrect exposure. The only way I have found to use lenses that do not have the A setting is to use a known accurately metering f/stop and interpolate the exposure from there.
Canadian Rockies,

Thanks for correcting me. I was a bit hasty with the typing. It is of course possible to use the DOF preview lever method also to meter with the M and "K" lenses. I have found that this will still produce overexposure when stopped down on the lens.

As you rightly point out, the best method is to meter at an aperture you know to work correctly and then adjust aperture/shutter by the same number of stops to achieve the image you want.
03-18-2009, 04:37 AM   #732
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A couple from my M 50mm F1.7:





Both taken with available light F1.7 at an exhibition centre (Focus on Imaging). I like the way using the M lenses makes me stop for a moment and think a little more carefully about what I am about to shoot. I still take opportune images and some may get away but what I do get tend to have more thought behind them.

Neil
03-18-2009, 05:03 AM   #733
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QuoteOriginally posted by regor Quote
Thumbs up for this one. I especially enjoy the bird sitting in the treetop.
03-18-2009, 08:21 AM   #734
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Is there a way to have the light meter on the bottom all the time with M lenses in M mode?

Because having to pull the trigger to get the optical preview thing is kind of a annoying.

That would be awesome if there was a way ..

Let me know,

-Isaac
03-18-2009, 09:56 AM   #735
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M 135mm f/3.5

This late afternoon, when the sun just hit our backyard. The numbers 1 and 6 are wide opens...

#1
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395077_resized.jpg[/IMGWIDELEFT]

#2
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395084_resized.jpg[/IMGWIDELEFT]

#3
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395090_resized.jpg[/IMGWIDELEFT]

#4
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395094_resized.jpg[/IMGWIDELEFT]

#5
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395100_resized.jpg[/IMGWIDELEFT]

#6
[IMGWIDELEFT]http://iloapp.stellaria.nl/data/_gallery/public/10/1237395107_resized.jpg[/IMGWIDELEFT]
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