dsnoke Loc: North Georgia, USA

Hi all,

I have rented the lens to try to see if I want to buy. I find that I have to use at least two full stops faster shutter or smaller aperture, according to my meter anyway, to get an acceptable exposure. I have no exposure compensation set. I find nothing on this in the manual, nor by searching UHH. With my 18-105mm lens and 55-300mm the meter indicates a correct exposure.

Since this is the first FX lens I've tried on a DX body, I'm wondering if this is a normal effect due to having a lot more light coming through this lens compared to a DX lens? Or have I got something set funny in the menus? Or am I missing something?

Thanks,
Dick

MT Shooter Loc: Montana

Are you guessing at the difference?
Take two identical shots, same ISO, same aperture, same shutter speed, in manual mode first using the 105 micro, then with your 18-105 also at 105mm.
Compare and post these two shots to demonstrate your issue and results.

dsnoke Loc: North Georgia, USA

No, I'm not guessing, but I will conduct the requested experiment and present the evidence tomorrow. The question is serious: Is there some property of the lens that would confuse the meter or otherwise cause an incorrect reading?

Joexx

When you do the compare of the two shots, I suggest you check the Meta data on each shot. This will tell you what the camera thought it was doing. It may not be the same as the settings you think you are using. The camera uses information electronically read from the lens and makes decisions based upon internal information it has for that lens, as well as basic stuff such as ISO, speed & f-stop you set. For example, if there was some sort of lens correction that should not be there, you may be able to see this in the data.
As long as the camera is getting info it can process correctly from the lens, it should do fine with both lenses.

Another thought. Does this lens work correctly on a different camera? If your shots are 2 stop over exposed, perhaps the rented lens has a problem with the diaphragm not working correctly. Normally, the diaphragm is wide open. When you take a picture, it stops ( closes) down to the f-stop you set. It could be that the diaphragm is "sticking" or not closing down correctly or fast enough.

Bultaco Loc: Aiken, SC

This may answer you question FF lens on crop body. https://www.youtube.com/watch?v=YDbUIfB5YUc

SusanFromVermont Loc: Southwest corner of Vermont

Dick,
Just some things to think about, because there are all sorts of things that can affect the image:
1. What metering mode are you using? Matrix, center-weighted, spot.
- Matrix reads the whole scene, averages the light and performs accordingly.
2. What shooting mode are you using? Auto, aperture-priority, shutter-priority, manual.
- Manual gives you full control, the other modes let the camera make decisions for you.
3. Have you compared the images on your computer monitor, and then tried some test prints [multiple images on a sheet]? Are they coming out overexposed in print when the computer screen shows them to be overexposed?
- Brightness of the LCD on the camera as well as of your computer monitor can affect how the image looks, and it is possible that needs adjusting.

That said, I have found the same issue with my D7000 - overexposure at supposedly correct settings. This does not always occur, but it happens often enough that I tend to either bracket automatically or check the image and histogram to see if I ought to make some adjustments. Some macro subjects don't hold still long enough to get off more than a few shots, so making sure you get a good one is doubly important. No time for checking and re-shooting!

I shoot in Manual most of the time and can adjust for over-exposure by putting the exposure level a couple of marks toward underexposure. But I still like to use multiple exposures to compensate for how the camera/lens "sees" the subject.

Susan

mikeroetex Loc: Lafayette, LA

You have to eliminate more variables and give more information as to how you are determining the two f-stop difference. I assume the two zooms are set at 105mm? And you are shooting the same subject in the same light conditions, same focus point? Are you in spot or matrix metering? Is the 105mm set at 5.6f aperture to be at same as zooms? Those kit lenses have variable f stops, so at 105 on either one, you are likely at a minimum of 5.6f already, compared to the 105mm. So that could account for 2 f-stops already.
I have never noticed any f-stop difference on my lenses, all else being equal, other than dramatic increase in sharpness. But I rarely use the kit lenses anymore. I'm usually switching from fixed aperture zoom lens to prime lens. Do you have any photos to post with exif data? These members here (not me) have some pretty great analytical skills.

romanticf16 Loc: Commerce Twp, MI

Once the lens is in "micro" mode for close up work it will require more exposure as you have changed the relative focal length of the lens by selecting this setting. The f stops on both lenses are for "normal" use, not the "micro" close up setting.

dsnoke Loc: North Georgia, USA

Hi everyone,

I did some experiments this morning to compare exposures using by trusty 18-105 mm dx lens and the 105 mm fx macro lens,
both on my D7100 body. Following are five pictures, as follows:

Pictures 1 and 2 were both taken 5-10 minutes before sunrises. The first was taken using the 18-105 mm lens.
The meter gave a correct exposure of 4 seconds at f/5.6 using ISO 100 (due to the low light.)
The second pictue was taken with the 105 mm macro lens. The meter gave a correct exposure of 4 seconds at f/5.6 using
ISO 100. At that point, I thought I must have made some mistake yesterday, and everything was behaving as I expected.

Then I moved to a different location where I knew I had flowers to shoot. Pictures 3, 4 and 5 are from that location,
all about 30 to 35 minutes after suunrise, with much better light. Since I still had the macro lens mounted, I tried a
shot with that lens and trusting the meter. Picture 3 was what the meter read (1/10 sec, f/36, ISO 800), but the result
is so far over exposed as to be unusable. I then cranked the aperture and shutter to an exposure that worked, and picture
4 is the result, requiring a shutter of 1/1000 of a second with the same aperture and ISO. Then I switched to the
18-105 mm lens for picture 5: 1/6 sec, f/5.6, ISO 100, also what the meter said was correct. The difference between the
last two seems reasonable given the ISO difference and changing light.

I'm at a loss to explain the wild variations between lenses. I'm also at a loss as to how I get f/36 out of a lens that
is supposed to have an aperture range of 2.8 to 32. In fact, for a later shot, the metadata says I had f/60!!!

Sooooo, any ideas??

Thanks,
Dick

18-105 mm

(Download)

105 mm macro

(Download)

105 mm macro

(Download)

105 mm macro

(Download)

18-105 mm

(Download)

mikeroetex Loc: Lafayette, LA

Dick, I can't wait to see what the Hoggers come up with. This is beyond the depth of my knowledge. If I had to guess, I'd say 1) lens contacts may need cleaning and camera and lens are not talking. But I still think 2) it's your metering mode. Pattern metering has to have something to do with it.

When you shot the rock with about the same composition and reflective surface, camera gave a similar result. But the flower has a lot open space behind it and less reflective. Meter may be catching a lot of light (or lack of) not coming off the flower.

Were you hand holding? Because I see a different composition, distance to flowert and frame fill in all 3 shots. At that close range and a tight shot, even a very small shift of hands and focal plane could give a different light reading. The flower might even move in the wind. I would be shooting single point focus, spot metering and for such experiment, on a tripod so I had exact positioning for each shot.

In fact, I would try experiment in a much more controlled scene, indoors. And them again, like I said... this is a pure SWAG! Others with more skill and knowledge will probably peg it down for you.

Joexx

Dick,
Several comments. It is NOT the DX vs FF that is causing this. I have several DX & FF cameras and lens (Nikon) and I have NEVER had an issue. Yes, there are metering differences, but the likelihood of that causing the problem you describe is very small. If you do a spot metering on one bright spot, you will get an incorrect setting, but this does not seem to account for your issue. your first picture does not have any uneven lighting.

Please check my initial suggestion. It seems to me that the rental lens has an issue with stopping down the diaphragm. Your latest comment seems to confirm this.

You said that the metadata shows aperture settings that are not in the lens range. This would seem to confirm that there are issues with the lens. either the electronics ( contacts or electronics), or the mechanical action of the aperture.
Again, try it in a full frame camera , if you can get access to one. do you have the same issue?

Just a general suggestion. I am not sure if you were using this settings, just to show issues with the lens, or if these are settings that you often use. but just in case you often use these settings, a few suggestions IMHO :-)
Stay away from small apertures, such as the f/36 of your test shot. you are generally much better off using an opening in the mid range of the lens, such as f/8 - f/11. Of course, this will vary depending upon lens. you can check specific lens tests for where your lens has the best quality.
But, you almost never want to be at f/36. ( depending upon lens & camera above ~ f/11 you may start to have issues with diffraction).

Also, the D7100 does really well at ISO's quite a bit higher that ISO 100. This means that (instead of 1/6 s, F/5.6,ISO 100) if you had shot the picture at 1/25, f/5.6, ISO 400, you would have a faster shutter and far less camera shake. at 1/6 you need a tripod. at 1/25th you may be able to get away with hand held. Or try ISO 800 and set the shutter to 1/50th. With the D7100, and depending upon what you are doing with the picture, you may not be able to tell the difference.
Likewise, for the 1/10 sec, f/36, ISO 800. You would be much better off with 1/200, f/8,ISO 800, or perhaps 1/100, f/8,iso 400
There are lots of discussions on this site regarding use of ISO, aperture & shutter speed.
A good link to check out equivalent settings is: http://www.scantips.com/lights/exposurecalc.html

dsnoke Loc: North Georgia, USA

Thanks for all the comments.

I have resolved this as follows. First, the metering appears to be correct if the picture is uniformly reflective and fills the frame. As soon as there is any significant variation in the lighting, things go wrong. Three full stops underexposure is consistently the difference in any light.

Second, both because of the first problem and because the camera think the lens has a far greater aperture range than it does, I suspect something is amiss in the electronics/connection between the lens and camera. If I had bought this lens, I would ask for a refund. But since I rented it, I'll simply return the lens and describe the problem.

Thirdly, based on what the lens can do and what I like to shoot, I can do as well with the gear I have. No GAS required. I'm not interested enough in macro photography to invest in a lens, a focusing rail, and photo-stacking software. I'mm satisfied with my 55-300 mm lens combined with a +1, +2 or +4 magnifying filter.

Joexx, I do understand your comments on using ISO variation to stay in a more "middle" range of apertures. I tend to do as you recommend when shooting most things. In this case I was using small aperture to see how much or little DOF I could get with this lens.

Thanks again,
Dick

Joexx

Yeah, I figured you probably knew that, but I had no way of really knowing.
Glad you solved your issue. Regards, Joe