Bug report

Bug summary

I think position of ticklabels on colorbars with LogNorm is sometimes weird, and I believe it wasn't like this in earlier versions, but I haven't checked that now. Namely, in the example below, I would expect the lowest ticklabel be at 5x10-1, not 6x10-1 as it is now.

Code for reproduction

plt.imshow(np.random.random(15**2).reshape((15, 15))+0.5, norm=LogNorm(vmax=2, vmin=0.5), cmap='coolwarm')
plt.colorbar()

Actual outcome

Matplotlib version

• Operating system: Ubuntu 16.04
• Matplotlib version: 2.2.2
• Matplotlib backend (print(matplotlib.get_backend())): inline
• Python version: 3.5.2
• Jupyter version (if applicable): Jupyter Lab 0.33.6